Unwritten no-nos like in-flight grooming aside, most passengers’ plane pet peeves tend to rankle them for two key reasons, veteran fliers say: a perceived sense of entitlement or invasion of personal space.

Airlines are packing more seats on planes, especially in the economy section, and legroom is scarce in most rows. That has many passengers cringing every time fellow passengers recline their seats, hog the armrests, crawl over them to get to the bathroom or put all their weight on the chair in front of them when they stand up or sit down…

Shawn Kathleen is the former flight attendant behind the Instagram and Facebook account Passenger Shaming, where travelers share egregious in-flight antics that sometimes go viral. (She goes by her first two names to maintain partial anonymity.)

She says she, too, is irked by passengers who ignore unwritten deplaning rules. And travelers who watch movies or videos without headphones (some of them really not appropriate for nearby kids) or plop their bare feet onto everything from the armrest to the bulkhead. Then there’s the “important business guy” who shouts into his phone on a very important business call while boarding.

“I’m like, ‘Are you walking somebody through surgery right now? ” she says. “If it’s not that life-changing moment, I feel like maybe you could hold off for a second.”