What are your favorite/most interesting sayings, aphorisms, metaphors, similes,etc.

When kids think they are know it alls, I counter with "Look I know more about being young then you do about being older". Stumps most of them.

As is typical for most all teenagers, my son thought he knew everything. I finally got fed up and told him, "You think you have all the answers, but you don't even know the questions yet!"