Sometimes you fold what seems to be the best hand with the intention of gaining a loose read on someone. If they continue to act erratic and/or overaggressive in other hands, then you have more info next time you hold something to take a stand with. If it turns out they play tight from then on, chances are they hit a lucky board and actually had you beat the first time, when you folded what "seemed" to be the best hand.

It's just part of the game. You show respect for players until they prove to be disrespectful.

last night I folded several hands to an aggressor before taking half his chips with a pair of threes. He manufactured a fantastic read for me that allowed me to give up on previous winning hands and still profit from him when my read solidified.