Flyers have been revealing some of the most horrifying examples mid-flight behaviour. Photo / 123RF
Flying is often a testing experience on the best of days - it's normally cramped, the food is often bland and turbulence doesn't help.
And neither do passengers who exhibit shocking behaviour.
Flyers have been revealing some of the most horrifying examples on an internet forum, from strangers putting their feet on the laps of seatmates, with a smile, to projectile vomiting.
People complaining of others getting in their personal space was a big complaint on the thread, MailOnline reports.
Christina Knox wrote on Quora: "I once was flying from the U.S. to Korea. It's a long flight; about 12 and a half hours. The plane wasn't completely full, and I was in the middle section of a row of seats.
"After the flight took off, an old Korean Ajumma lady laid down in the vacant seats and placed her socked feet in my lap. Ugh.
"I gently pushed them off my lap and said, 'Let's just keep them down there, ok?'
"She smiled and waved her hand at me, babbled something softly in Korean (Unfortunately I didn't speak much of the language at the time), and then placed her feet back in my lap. Yikes."
While Dawn Lwa also wrote how she had a disturbing encounter with another passenger's feet.
She said: "I'm a seasoned traveller so it takes a lot to rattle me. I was just on a flight, middle seat. The woman behind me took off her shoes, stuck her bare feet through the slots on either side of my chair and let them sit on both of my armrests. Disgusting.
"I didn't say a word. I just turned around and stared straight at her until she became uncomfortable and moved her stinking feet off my chair."
And Shane Told explained how his seatmate also annoyed him after taking his shoes off. He explained: "I was in the aisle seat and a middle aged man in a suit across from me took off his shoes. Pretty standard I thought… Then he took off his socks and I thought that was a bit abnormal.
"But afterwards he reached into his suit jacket pocket and pulled out a set of nail clippers. He lifted his knee up, foot onto his seat and was about to clip his big toe nail when I said 'You can't actually be serious dude?'
"To which he responded with 'oh, yeah I guess maybe it's a bit weird to do that here'."
David Lean had an unfortunate experience, too - when his seatmate projectile-vomited.
He said: "One moment the guy in the middle seat next to me was reading a book, the next his chest spasmed out, his shoulders arched back, his chin arched up and a fountain of spew flowed up and over to the seat in front.
"It was impressive. He did not get one drop on me, the guy next to him or even the seat back in front of him. It just started and cut off cleanly."
Gbemi Oshifade said: "On a night flight from Lagos to London with a stopover in Milan, Italy.
"A dude behind me had been sleeping across the seats as they were empty, he was snoring for a while when I heard him rustle and then disgustingly hawk his throat, he must have thought no one was awake and just spat loudly.
"I hoped into a tissue but it sounded like into the corner of his seat."
On a flight from Cairo to London, nervous flier Abdullah asked his seatmate for some moral support but was left even more fearful.
He said: "An Egyptian guy was next to me. My phobia of flying started to run in my blood. I decided to talk to him in order to hopefully become calm.
"I said to him: I have got a phobia of flying. Would you mind talking to me for a while?
Lille Mingo couldn't help but be disturbed when he peered across to his seatmate to see what he was typing in his phone.
He explained: "I had just found my seat when this very friendly looking lady in her 30s came and sat down next to me, as there was still eight to 10 minutes till take-off she decided to take out her phone and went to Google, I was bored so I sort of sneak-peeked at her screen.
"'How to hijack a plane midair'... that's what she Googled. I began sweating and screaming on the inside... what was she up to?
"Seconds later she pulled out a big stack of papers that said 'dissertation on aviation security protocols' she looked at me and smiled, then realised what I had seen. I said 'pheeew' and we both laughed."
User Arthur Coldwells says one of his fellow passengers on a plane tried to blatantly steal his girlfriend's designer Tom Ford sunglasses.
He said: "During the flight my girlfriend somehow dropped the glasses that had fallen out of her purse that was on her lap, and they slid backwards and under her seat.
"It was so cramped that no matter how much we wriggled we couldn't see them, and couldn't have reached them even if we had been able to spot them. So I said we'd find them when we landed.
"The plane landed and people started to get off. As the person in the aisle seat next to me had stood up we had a little wiggle room, so we also stood and turned, and searched around. And searched, and searched.
"But then when we finally looked up past the backs of our seats, one of the young women sitting behind us (early twenties I'd say and quite well dressed) was frikkin' wearing them!"