I've had a few:
Clutch - Soccer team as a kid, because I always scored that clutch goal, stuck with me when I blew my first clutch on my car....
Duck - I used to work as a dock loader (loading buses and semi-trucks) and there was always so much crap that bosses dumped on us, as well as other guys there whose lives were always "so hard" that whenever 'it' hit the fan, I just shrugged it off and kept working. My boss said that "##### rolls off him like water off a Duck's back."
Quags - Rugby. Dont want to talk about it.