"We do not know what we do not know."
-I've see this variously attributed to Wittgenstein, Confucius and Donald Rumsfeld. Oddly profound.

"If you get to thinkin' you're a person of some influence, try ordering somebody else's dog around."
-Will Rogers

"I care not for a man's religion whose dog is not the better for it."
-Abraham Lincoln

"If pro is the opposite of con, what is the opposite of progress?"
-Mark Twain