When was the last time you saw some guy shaved his face while in his seat?! Or was he shaving his legs? Legs I can totally understand doing at the seat, because you really need a mirror to do your face.

Seriously though, it is a enclosed space so yes I would consider nail polish offensive; NO ONE needs a manicure that badly. But I am also the guy that won't bring overly smelly food on board either just to be considerate. Snoring, drooling, burping, and farting are things that are tough if not impossible to control, so you really can't put them in the same category.