I gave up using urinals years ago, and my reasons are absolute. I had my share of guys trying to... you know. It's not really polite if you're not the one doing it first.

Ruler number #1: Brush your teeth. It seems that a lot of guys doesn't know what a toothbrush is. Also, "whiskey" does not qualify as mouthwash. I can't believe that I've had to say that to more than one of my friends.