RPG Cliches
http://atrocities.primaryerror.net/rpgcliches.html
Heres an example from the list:
Facial Hair Law. The style and amount of facial hair on any character will indicate alignment and general tendencies: goatees are either evil or poseurs, full beards are lovable big guys, long beards indicate wisdom, and scraggly, unkempt beards mean insanity. This is never more true than in fantasy games.
Some quite funny and others are scareily true!