Airports can be strange places.
Amid the frantic rush to make a business appointment or get the family somewhere hot as quickly as possible, they represent a kind of compulsory no-mans land for hours of waiting around.
While some airports have risen to the challenge - the butterfly house and cactus garden at Singapore's airport being among the best examples - others have fallen woefully short of the mark.
And now pilots have let the flying public know exactly where to avoid touching down, in a series of posts on online forum website Reddit.
1. Los Angeles (LAX), US
The seventh busiest airport for passenger traffic in the world, this airport prompts vitriolic recollections from pilots and fliers alike.
"There's construction everywhere, it's always a mess to taxi around," said one Reddit user.
The worst airports in the world, according to pilots
The worst airports in the world, according to pilots
1/10 Los Angeles (LAX), US
The entrance to Los Angeles International Airport, one of the least liked in the world
2/10 Kathmandu (KTM), Nepal
3/10 Paris Charles de Gaulle (CDG), France
Passengers waiting for their flight at Charles de Gaulle airport in Paris
4/10 Manila Ninoy Aquino International Airport (MNL), Philippines
5/10 Chicago (ORD), US
6/10 Heathrow (LHR), UK
7/10 Pyongyang Sunan International Airport (FNJ), North Korea
8/10 Sao Paulo-Congonhas Airport (CGH), Brazil
9/10 La Guardia Airport (LGA), New York City, US
A runway at the disliked La Guardia airport in New York City
10/10 Madrid-Bajaras (MAD), Spain
"I hate LAX," said another, "It's the worst airport in the States."
Opened in 1930, the airport does at least have a space-themed restaurant perched 70 feet off the ground, and is one of the most famous locations for plane spotting.
2. Kathmandu (KTM), Nepal
Actually called Tribhuvan International Airport after the current king's father, this small airport is bedded down in the Kathmandu valley outside the city centre.
"Kathmandu is the worst airport in the world by far," said one Reddit user.
"A glorified bus station running at 600 per cent capacity with no amenities and confusing security."
Another said: "There was security when you went through there? I got asked if I had a knife on me. That, and the airline staff looking at my bag."
3. Paris Charles de Gaulle (CDG), France
The second busiest airport in Europe after Heathrow, the airport is not always affectionately known as "Roissy" to the French.
Opened in 1974, the airport's chime before all its intercom announcements became so well-known that director Roman Polanski featured it in one of his films.
But this has not saved CDG from the scorn of passengers.
"Don't ever go in if you want to leave within a week," said one.
"It loses my luggage 50 per cent of the time. I've accidentally gone through security with a metric tonne of prohibited items, which they never noticed.
"And once my entire flight got to our gate without being issued boarding passes."
4. Manila Ninoy Aquino International Airport (MNL), Philippines
The airport is named after a politician who was actually assassinated there - a political opponent of the president in 1983.
Built in 1935 and hit by fires several times throughout its lifetime, it is dwarfed by the shining example of airports such as Singapore for the more seasoned pilot.
"It's hard because all the other airports in Asia are palaces," said one pilot. "But MNL remains in a time warp."
5. Chicago (ORD), US
Actually called O'Hare International Airport, its terminals come in for weather-related criticism.
"They get an inch of snow and it's like the whole goddamn airport needs to shutdown so they can decide on a course of action," said one pilot.
6. Heathrow (LHR), UK
Terminal 4 is especially bad, apparently, despite the £200 million spent on it ahead of its 1986 opening.
Pilots did not have many specific criticisms of the well-known international airport, although a number responded to the call for examples of terrible airports with "definitely Heathrow", or variations thereof.
7. Pyongyang Sunan International Airport (FNJ), North Korea
A particular kind of dislike appears reserved for an airport which has the same gate for arrivals and departures.
Users bemoan an "internet room" with no actual connection to the rest of the world, and passengers' holiday snaps being inspected by airport staff before they are allowed to leave.
8. Sao Paulo-Congonhas Airport (CGH), Brazil
Weather is also a problem for this airport - one which was placed in a highly populated area because of all the mountains nearby.
A slippery runway caused one plane to overrun in 2007 and crash into a warehouse, killing all the passengers and pilots onboard.
And despite the drainage system brought in after the tragic accident, the entire airport was shut for six hours in March 2016 following heavy downpours.
One pilot simply said: "To be avoided."
9. La Guardia Airport (LGA), New York City, US
Many American pilots singled out their experiences landing at this Big Apple airport for particular scorn.
It is, according to one professional, "awful".
They said: "There are crossing runways - one to takeoff and one to land - constant ground delays to takeoff and to get to the gate.
"Cramped terminal and it just looks outdated."
First opened in 1939, it might be time for an upgrade.
10. Madrid-Bajaras (MAD), Spain
The full title of Spain's busiest airport is Adolfo Suarez Madrid-Bajaras Airport, after the first prime minister of the country following Franco's dictatorship.
Yet it does not appear to be held in high esteem by many.
"It is an awful place. The long narrow terminal means walking kilometres," said one user.
"Prices at restaurants and machines are outrageous. In general, the signage is rare, chaotic and not logical."
- More about:
- Los Angeles
- Rio De Janeiro