Think not of what you can do, but of what you cannot!

Never underestimate your mistakes, for they are the fount of all experiences and beginning of all truths.

Whenever I want to listen to some silent music, I always play blank tapes.

PC: can also stand for politically corrupt!!

I don't suffer from insanity, it's my sanity that suffers from me.

By logic, it's no longer a secret when you say "The secret of sth is....".