"Never argue with a fool, they will lower you to their level and then beat you with experience"
"The more you learn, the less you know"
"Don't tell me what to do and I won't tell you where you have to go"
(that's my favorite actually, because that's how I feel when people start to "teach me how to live")
"Life like a zebra: white stripe, black stripe, white stripe, black stripe... a*s"
I can think of more, but not now... :)