I always liked Forrest Gump's folky way of putting it: "Stupid
   is as stupid does". its become a glib phrase - but its short and
   sweet and says it If I do something stupid, that's what makes me
   stupid. But it doesn't make the person fundamentally stupid, or
   everything they say stupid. Just the actions. Lots of folk
   wisdom and proverbs carry a deeper meaning - that's why they
   have sticking power. Or because they're catchy. "Dead as a
   doornail" - nobody stops to think "What's a doornail?" But I
   digress. "