"What's mine is mine and what's yours is mine."
"Stupidity killed the cat. Curiosity was framed."
"Parents spend the first part of our lives teaching us how to walk and talk, then the rest of our lives telling us to sit down and shut up."
"Newscasters are the people who tell you 'good evening' and then tell you why it's not." (Although that wasn't really a catch phrase...)
"If practice makes perfect, but there is no such thing as perfect, and school is practice, THEN WHY THE HECK PRACTICE?!"
"It takes 42 muscles to frown, 28 muscles to smile, but only 4 muscles to reach out and slap someone."
"When Life gives you lemons, squirt them in Life's eye, and see how much Life likes lemons then."
"Always remember you're unique. Just like everyone else."
And my all-time favorite:
"Don't knock on death's door. Ring the bell and run. He hates that."