Maybe we should categorize this one as a phrase you should never hear -- especially from a child. It means you forgot to remove those NSFW ("not safe for work") pictures from your laptop. Please don't subject that little kid sitting next to you or me, for that matter, to your "Hangover" bachelor party photos. In fact, why are you even taking pictures of stuff that should "stay in Vegas"?
8. "Listen, captain, I think your attitude stinks!"
Maybe pilots are no longer paid a royal wage, but you better believe every one of them is still king (or queen) of the cockpit, so pick a fight with them at your peril. Just ask the flight attendant who dared argue with such a monarch on a flight from Sao Paulo to Chicago earlier this month. The pilot diverted the flight to Miami and then, allegedly, kicked the offending crew member off the plane.
9. "Wait a minute, your ticket cost $300 less than mine?"
Mom always said, don't talk about religion and money -- so don't ask your seatmate what his ticket cost -- or risk spending the rest of the flight wishing for the oxygen mask to deploy. On the other hand, if it galvanizes you into signing up for real-time, e-mail alerts or doing something really cool like finding deals via Twitter -- well, that's a good thing.
10. "Do you know who I am?"
This is the one, sure-fire way to turn everyone against you but, unfortunately, the people who use this phrase tend to have the sensitivity of a Simon Cowell. Still, try a snappy comeback: One of my employees swears she heard a passenger use this immortal phrase on a flight attendant, who smiled sweetly and said, "You're right, I don't know who you are. But let's take a look at your ticket, I'm sure we'll find the answer there!"
OK, now let's turn the tables: What should you say on a plane? How about nothing. Blessed silence is vastly underrated!
This work is the opinion of the columnist and in no way reflects the opinion of ABC News.
Rick Seaney is one of the country's leading experts on airfare, giving interviews and analysis to news organizations, including ABC News, The New York Times, The Wall Street Journal, Reuters, The Associated Press and Bloomberg. His Web site FareCompare.com offers consumers free, new-generation software, combined with expert insider tips to find the best airline ticket deal.