Complaints about long flight delays and sub-standard accommodation are absolutely justified but some travellers are just impossible to please. From tourists complaining about too much sand on the beach to those blaming travel agents for their pregnancies, some people are never satisfied.

Click through the gallery for our ranking of the world's most bonkers travel complaints...

This person’s trip got off to a bumpy start when the airport transfer presented an unforeseen obstacle: 'The roads were uneven and bumpy, so we could not read the local guide book [sic] during the bus ride to the resort. Because of this, we were unaware of many things that would have made our holiday more fun.'

A travel advisor said she received a call late at night from one client visiting Rome, who complained that they had received a sandwich but the bread was not buttered on both sides and that there was no milk in the tea. After talking to the hotel, she found out the milk had been served in a separate jug, as is the custom.

One tourist blamed relaxed beach etiquette for her husband’s wandering eye, complaining: 'Topless sunbathing on the beach should be banned. The holiday was ruined as my husband spent all day looking at other women.'

There was a distinct lack of fireworks for this traveller when they set out for a spot of local sightseeing. They scolded the person who had recommended the day trip, stating: "You said the town was next to a volcano, but we went and there was no lava. I'm pretty sure it was just a mountain." Call us superstitious, but perhaps insulting some of the world's most destructive geological wonders is something you should think twice about.

One disgruntled tourist wasn't happy about the lack of fruit (or types of fruit) in their sangria, writing "Our jug of sangria didn’t have a wide-ranging fruit selection in it.” At least they're health-conscious.

It’s one of the most famous prehistoric monuments in the world, but TripAdvisor reviewer Dan G was disappointed when he visited, writing: "It’s a bunch of rocks... in a field. WOOOOOOOW! You’ll have to excuse the sarcasm, but the reality is that this is exactly what this 'attraction' is, you can’t even go up to them. Yes there’s some historical background... but that can be said of plenty of other, far better attractions that our country has to offer. Give it a miss, not worth the effort…"

One customer blamed her pregnancy on the travel agent, writing: "My fiance and I booked a twin-bedded room but we were placed in a double-bedded room. We now hold you responsible for the fact that I find myself pregnant." Another couple were incensed to find their neighbours had booked the same hotel, moaning: "When we got to the resort we found out that Bert and Mavis from down the road were also there. I hate Bert."

One of the most magnificent examples of ancient engineering, The Great Wall of China is 'too long' and 'just a wall' according to some visitors. Another traveller was left pretty unimpressed with this historic monument, complaining: "I didn't see the hype in this place, it's really run-down and old."

One unhappy parent was disappointed after being charged for her teenage daughter’s meal, writing: "The restaurant said 'children eat free' but my 19-year-old daughter still got charged for her meal." Another wrote: "My plane journey was a disappointment as the sky was too cloudy, obstructing my children’s view of the sea and ruining our game of eye-spy."

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One of the most popular destinations in the US, the Grand Canyon doesn't charm all of its visitors, one of whom said he thought the canyon 'could've been a little grander.' One traveller, who didn't expect bad weather, said rain and fog ruined the trip while another disgruntled visitor said: "It's just a big hole in the ground. It took me a long time to walk round it, downvoting until they build a bridge or something."

The Louvre is one of the world’s most popular museums, but Tripadvisor reviewer Palindromeman was seriously unimpressed by his visit. He wrote: "Musee du Louvre – bad. Short answer: bored… Apparently there is between 14 to 16 kilometres of boredom on offer at the Louvre. I could not do it." Of the Mona Lisa, he wrote: "She's small. Effectively A4 size… And that smile? She looks to me like she just pulled a bank job and got away with it."

Accusing the operator of 'false advertising' when she failed to spot any A-listers onboard her Celebrity Cruises holiday, one woman demanded a full refund for the injustice. And the bizarre cruise complaints don’t stop there – one traveller even requested that their cabin be 'better sound-proofed against the sounds of the sea.'

A male tourist at an African game lodge became disgruntled and self-conscious after seeing a visibly aroused elephant in the bush, claiming the encounter left him feeling 'inadequate'. But not everyone gets an eyeful on safari, with one guest lamenting: "I spent a whole week on safari, and didn't see any good animals. There was only a load of antelopes." Poor antelopes...

An incensed customer who visited Florence complained about queues at the Uffizi Gallery. A travel advisor explained, "They complained that there were queues at the Uffizi and I should have told them… even though I had encouraged the client to pre-book the 'skip the line’ tickets which I could do for him."

Most visitors to London want to tick Buckingham Palace off their bucket list but Tripadvisor reviewer Christopher H was less than impressed, writing: "Didn't excite me at all. What's the point of travelling to England to stand outside of Buckingham Palace. You can't go in. Is the queen [sic] so greedy she needs all 77,000 square metres and can't show off one of the grandest palaces in the world? Wow, a fence, whoop!"

It might be one of the most recognised symbols of Paris yet some visitors were not so impressed by this French landmark. Giving it a one-star review on Google, one traveller suggested it should be rebuilt while others called it ugly and unattractive. "More like awful tower," said another visitor.

Visitors to a water park were woefully unprepared, complaining: "We booked a day out to a water park but no one told us we had to bring our swimming costumes and towels. We assumed it would be included in the price." Another blamed the travel agent for missing their flights, saying: "We were not reminded to bring our passports and thought that we didn't need them."

Italian holiday company The Italian Connection has encountered some ridiculous complaints from its customers. The most ludicrous was from a tourist visiting Siena, who complained that 'there were far too many tourists and far too many Americans and British people.' Someone else felt the same about Disney World, having written to the park about it being 'too touristy'.

Apparently, some travellers who visited Machu Picchu in Peru didn't expect the ancient mountain city to be in the mountains and branded it 'too high' and 'too old'. Another one-star reviewer suggested that the remains of this Incan citadel would be improved with wifi.

Some customers complained after finding out their latest bargain actually was too good to be true: "We bought Ray-Ban sunglasses for €5 from a street trader, only to find out they were fake."

A family who booked a ski holiday were shocked to find that skiing was difficult, writing: "We went on a skiing holiday but we weren't informed that we would actually have to be able to ski." Another was disappointed by the weather, complaining: "It was far too cold on our skiing holiday."

One customer was extremely disappointed that he was not properly informed before getting into a hot air balloon: "There was no sign telling you that you shouldn't get in a hot air balloon if you're afraid of heights."

Another traveller was shocked to find fish in the sea, moaning: "No one told us there would be fish in the sea. The children were startled." Another was disappointed with the salty water, complaining: "The water in the Gulf of Mexico was too salty. No one told me that there was going to be salt in the water. It was gross."

One holidaymaker was irate after forking out for a hotel in London, only to find there was no ocean. They complained: "Our London hotel didn't have an ocean view." Another moaned: "We went to London and couldn't find the beach." We hate to be the bearers of bad news, but London is actually around 35 miles (56km) from the nearest seaside beach.

Cruise company Iglu Cruise received an entertaining complaint one year, with one couple seeking a full refund with the following complaint: "We usually come off our cruises having put on at least a stone in weight. We’ve come off this holiday having put on nothing at all. It’s just not good enough."

Size really mattered to one particular guest, who felt they’d been short-changed on their accommodation: "I compared the size of our one-bedroom apartment to our friends' three-bedroom apartment and ours was significantly smaller." Maybe a maths lesson was needed when they got home.

A particularly rude holidaymaker was outraged by his tour guide, complaining: "We could not enjoy the tour as our guide was too ugly. You can’t admire a beautiful view when you’re staring at a face like his." People in glass houses and all that...

There's nothing worse than torrential rain when you're expecting a sun-kissed escape, but one angry tourist wished she’d just stayed at home, writing: "The weather at home was nice whilst we were away so the whole holiday seemed a bit pointless." Another complained: "It rained. We didn't know it ever rained in Spain." One more wrote: "Why did Thomson let us book the holiday if it was going to rain all week?!" Well, the rain in Spain falls mainly on the plain, after all...

Trainee hairdressers were worried they wouldn’t be allowed into their hotels, asking: "The brochure stated: 'No hairdressers at the accommodation.' We’re trainee hairdressers – will we be OK staying there?" Once they were allowed in, they felt discriminated against, writing: "We’re trainee hairdressers and we think they knew it and made us wait longer for drinks."

One tourist was disappointed after a trip to the zoo, writing: "The animals at the zoo looked very sad and it made our children cry. Can’t they train them to smile?" Another visiting Yellowstone National Park moaned: "We had to cut our trip short to Yellowstone because we were informed that they don’t cage the animals at night for our protection." Clearly animal welfare was not a priority for these guests.

Meet the world's ugliest animals we can't help but love

Who knew towels were such a bugbear? One holidaymaker moaned: "The maid who cleaned our room made our towel into a swan shape. I don't like swans." Another complained that they couldn’t tell the difference between the towels and the bathmats: "The bathmat was too similar to the hand towel; I kept getting them mixed up."

One lady was so distressed that she threatened to call the police when she claimed hotel staff had locked her in her room. But it turns out she had just got her wires crossed, interpreting the ‘do not disturb’ sign hung on the back of the door as a warning to not leave the room.

For some, holidays are all about catching a few rays, but one angry customer didn’t manage to get bronzed at all, complaining: "We were told we would get a great tan, but we stayed inside all day and didn't get one." Another complained they caught too much colour, writing: "I got sunburned. They should warn you that the sun is brighter in Mexico than it is in England. I would have worn sun cream if I knew."

In what might be the most mind-boggling complaint of all, one Brit abroad complained: "The beach was too sandy. We had to clean everything when we returned to our room." Another tourist was disappointed by the pristine nature of the sand on their holiday, writing: "We found the sand was not like the sand in the brochure. Your brochure shows the sand as yellow, but it was white."

The laws of science meant nothing to this traveller, who couldn’t stand the heat: "We had to line up outside to catch the boat and there was no air-conditioning."

A British woman from Blackburn complained to the travel operator Thomas Cook that her Benidorm holiday in Spain was ruined by 'too many Spanish people.' The 81-year-old traveller suggested the Spanish ''go somewhere else for their holidays' and demanded a full refund. Another tourist also called for siestas to be banned, saying shopkeepers were 'lazy to close in the afternoons' when she needed to buy things. How dare local people have their own culture...

One British traveller was annoyed at the disparity between flights to the UK and to the USA, moaning: "It took us nine hours to fly home from Jamaica to England… it only took the Americans three hours to get home." Another was appalled at a seat mix-up on the plane, complaining: "I booked the window seat for myself and the middle seat for my wife but the tickets put us in the opposite ones."

Another visitor to Spain was unimpressed with the amount of Spanish people in the country, writing: "The receptionist speaks Spanish. The food is Spanish. Too many foreigners." Another complained: "Why doesn’t everyone speak English? We went to Spain and no one understood English. We will never go back there again." That's probably good news for Spain.

A picky holidaymaker hated the food on his trip to India, moaning: "On my holiday to Goa in India, I was disgusted to find that almost every restaurant served curry. I don’t like spicy food at all." Another tourist was disappointed by the Greek food on offer, writing: "Food in the Greek hotel was too Greek. We had to eat in the nearby fast-food place."

Now read on for more astonishing tales of tourists behaving badly, from smashing sculptures to defacing ancient monuments