Favorite quotes?

I was in the security line at John Wayne Airport in Orange, CA, a couple of weeks ago when I saw a man with a t-shirt that said, "I became insane, with long intervals of horrible sanity. --Edgar Allan Poe"

"Did he really say that?" I asked.

"Yes," he said.

I've checked it out. He did. But he wasn't trying to be cute.

Perhaps you have some more uplifting quotes you'd like to share?