How come so few people know this? Hygiene -- that's your primping, cleaning, washing, etc. -- belongs in your bathroom --your bathroom -- and rarely anywhere else.
Why? Because there's bacteria and germs associated with your hair, makeup, nail clippings and eyelashes flying everywhere.
Ladies and Gentlemen -- do not brush or comb your hair on public transport, at a restaurant, or in someone else's car. Or home. Do it at home -- and then leave it. Or sneak into the bathroom. But not out in the open.
Ladies and Gentlemen -- do not clip your nails -- fingernails or toenails -- anywhere but your own home bathroom. No, not even in the gym locker room. (Someone did this the other day in my gym locker room...yecch.) Fingernails are gross. Keep them in your bathroom garbage can. This is never okay at the office.
Ladies -- do not apply makeup in public, and especially not on public transportation. It's unseemly, and gross to those around you. At the sink in a restroom is fine; but not at dinner, with friends, on the train, etc.
And never ever floss in front of other people.
Keep your hygiene at your house. Those around you thank you.