I have several beautiful mirrored compacts (pressed powder), which I will use at a table to quickly refresh my lipstick. Anything beyond that, the ladies' room.
BIL blows large, horking snots into his dinner napkin, then opens it to look at his snots at the dinner table. I had to leave the room. Also, people who spit; hork, then send a hocker flying - makes me nauseated.
Airplanes, I wouldn't dream of brushing hair, brushing teeth, etc. unless using the lav. Usually wait until deplaning.