I see what you mean, and for the most part I agree. I don't show my wins every time. You could make the agrument that if they folded, I DID have the nuts, whether I show or not. My hand WAS good enough to win.
But if I had 7 2 os and managed to get my opponent to call a bet 3 times, only to fold at the river - I would show that 7 2. If nothing else, just to piss em off. You can get people to make even dumber bets when the whole table just watched them get their ass kicked.
I've watched people virtually curl up into the fetal position, literally not knowing what to do, after a couple shows, a couple mucks, and a lot of wins.
Actually, as far as that goes - when the situation is reversed, if I fold to a bet, I just assume the player has what I put him on, and don't think twice about it - UNLESS he shows a bluff. Then it sticks with me - for half a hand - lol