But I think that you are defining "mistake" too narrowly. It seems (and I could be wrong in how I am interpreting your message and if so, I apologize in advance) that you are only looking at what it costs you when you play hands such as QT that go on to lose. But you are not looking at what it "costs" you when you don't play hands that go on to win such as AK. Folding AK is a "compounding" mistake because you miss out on what you could gain from bets on the flop, turn and river.