If you build a man a fire he will be warm for a night. If you light a man on fire he will be warm for the rest of his life.
That one always gets me (I enjoy gallows humor). I wonder how many people don't get it? Like my brother, who is very smart, didn't understand the saying "it's always in the last place you look." I had to explain to him that when you find something you're looking for, you generally stop looking for it any more. (Duh!)