What’s the one thing you should never do on a flight?

By Lauren Wilkin

As the vacation season begins, you can expect to also see an increase in viral videos of “disgraceful” passenger behavior.

Thomas P. Farley — also known as Mister Manners — a New York-based etiquette expert, has shared the one thing you should never do on a flight: steal the middle seat armrests.

It's objectively the worst seat on a plane, and so Mister Manners says extra care should be taken to ensure the middle-seat passenger is comfortable throughout their journey.

And in a crowded environment, the scarcity of armrests becomes a sensitive subject.

“In a three-seat layout of window/middle/aisle, the two outer passengers are guaranteed at least one armrest,” Farley says.

He explains that everyone gets a perk apart from the middle-seat passenger.

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“The window passenger gets a view and a wall to lean on for sleeping. The aisle passenger gets easy egress for bathroom breaks and stretching.

“The middle passenger gets torture.”

Because of this, “ceding the armrests to that individual is a small but meaningful consolation prize,” he says.

And it's not just armrests that are the issue.

If you’re flying on a budget airline, space is limited, so sticking to your designated area is the least you can do to ensure a comfortable flight for everyone.

“No passenger — middle-seat or otherwise — may extend arms, elbows or knees beyond the narrow chasm of space designated for another seat.”

“‘Manspreading’ and ‘elbow-spreading’ are inconsiderate actions that make an already tight and uncomfortable journey that much more unpleasant for the person who is being encroached upon.”

So, next time you're taking a flight, consider the middle seat passenger before you stretch out for a nap.