Making any important decisions during the flight
Nothing encourages level-headed rationality like thin air, tiny seats, crying babies, and the perpetual smell of fart.
Drinking a giant soda right before departure
It’s the best way to guarantee you hear the captain say, “We'll be 28th in line for takeoff.”
Getting belligerent with TSA
You may be surprised to learn that the nice lady in the blue uniform shirt doesn't actually write federal aviation regulations. So asking her “why” you have to do anything makes you sound like a four-year-old who doesn’t want to put away his Power Rangers.