I call this "Saved By The Bell" syndrome. Remember when that was on 49 times a day and you hated it, but found yourself watching anyway? Ugh.
Anyhoo, for me it's Bugles. They are gross and styrofoam-y and salty, but if they are in front of me, I find myself eating them. Then I stop and reprimand myself - stop it! You don't even like these... Crunch crunch.
Any foods you just can't stop eating?