Your car isn't your bathroom. In the last five days, I've had the pleasure of witnessing drivers doing the following:
1. A woman putting on deodorant.
2. A woman doing her makeup.
3. A man shaving.
4. And, my favorite/most utterly repugnant, a woman popping multiple pimples in her rear-view mirror.
Aside from the obvious dangers inherent in performing these acts while operating a motor vehicle, they're just plain disgusting.
I also noticed that all four of these people had really beat-up, piece-of-shit cars. Coincidence? No, obviously not. These people are fuck-ups. Do your grooming at home. There's a reason everyone else does. Because it's repulsive to look at, and because they want to succeed in life.