Some may be tempted to stretch out their legs on armrests or prop up bare feet for the sake of comfort — or to eke out a little extra space while lounging.
But whether you're cruising solo or among a packed crowd, those in the business of good manners agree that feet on public seats is a faux pas.
"As soon as you get into public areas — which is transport, offices, airplanes, waiting rooms, anything like that — it's no longer yours. It belongs to everybody," said Suzanne Nourse, founder and owner of The Protocol School of Ottawa and co-author of "The Power of Civility."
"Etiquette to me, the true meaning of etiquette, it's not about the knife and fork: it's how we treat other people. And putting your feet up — where somebody else is going to sit down in a few minutes — is inappropriate."
Etiquette expert Karen Cleveland agrees there is a time and place to hoist your feet up.
"When you see people with bare feet and they put their feet up on a seat... or on the headrest of the seat in front of them in a theatre, it's disgusting," said Cleveland, writer of the column Finishing School.
"If you're at the beach, if you're lounging with your friends in your garden, that's a very different environment than being in a public forum sitting on a cramped subway or in a movie theatre," she added.
The fault with feet doesn't lie solely with propping them up in public but preening and grooming typically reserved for private time.
Civility Experts Worldwide president Lew Bayer recalled a story shared by a student who had observed a female sales agent picking at her feet at her desk which faced out towards a courtyard.
"I do often hear about things like that in the workplace, where whether it's picking your scalp or your nose or your feet — it's all disgusting," she said from Winnipeg.
Cleveland said personal comfort shouldn't supersede the feelings of your colleagues.
"I think even some footwear in the summer pushes (the boundaries of) what's appropriate in an office environment,"she said. "If you can wear it on the beach, it's not appropriate for the office. So flip-flops are a no-no. Barefoot or even in your stocking feet — definitely not."
Bayer said hygiene is also a concern when soles are bared in places where food is being served.
"Other people would say that 'It's bare skin. What's the difference if it's someone's thigh in their short-shorts or my bare feet?'" said Bayer, co-author of "The Power of Civility."
"But because feet are closer to the ground and lots of germs and waste and dog poop and chewed-up gum and all kinds of things, it is considered very rude — especially if your feet are unclean or not well-groomed to put them on other people's furniture."
So should someone feel inclined to swat away at strangers' feet encroaching their space or read the riot act to those committing the foot fault?
"If they're not directly impeding you, it might gross you out, but you don't need to walk around as etiquette police and tell people what to do. That's in poorer taste, I think," said Cleveland.
Bayer said it's appropriate to correct those who are clearly interfering with someone else, but the manner in which you do so is important.
"It's just like a child kicking the back of a chair in an airplane. It's not inappropriate for the person being kicked to turn around and say: `Would you please stop kicking me?'" she said.
"Some people are going to just swear and walk away and continue to do what they do. But there's a point where we have to have standards, and somebody has to have the courage to uphold them."
Nourse understands the need for comfort, such as taking shoes off on a long flight; however, "it doesn't mean I'm going to put them in somebody's face."
"Underneath in the chair in front of me, I might take my shoes off... but I think it's inappropriate if someone is sitting across from you to put your feet up."
The rules still apply even if someone finds themselves with few — or no — other people in close proximity.
"It's the same thing as something like double-dipping," said Nourse. "Just because nobody can see you, does it still make double-dipping — with the chips and dip — appropriate?"
Bayer said the desire among some seeking to carve out a little extra space may stem from social fear — but a lot of it is just habit.
"It's easier to pick up your bag if it's on the chair than on the floor, so we don't even realize that making somebody else stand so the bag can have a chair is rude.
"And if somebody said: `Would you mind moving your bag so I could sit there?' most people would happily move the bag, but we're not brave enough to ask — we just complain about it after," she added. "There's this lack of communication about what social expectations are these days."
Civility Experts Worldwide : www.civilityexperts.com
Finishing School: www.mannersaresexy.com
The Protocol School of Ottawa: www.etiquetteottawa.com