It's already in my signature, but maybe someday I will replace it with something else, so I'd like to repeat it, because I do think it's a very profound quote.
"The thing about witchcraft," said Mistress Weatherwax, "is that it's not like school at all.
First you get the test, and then afterward you spend years findin' out how you passed it. It's a bit like life in that respect."
Terry Pratchett (The Wee Free Men)