I think its offensive, in some ways just barely, other ways....can be a bad one. But, when called such things, being compared to things, 'You're Such A ****', I tend to just look them in the eye, dead-pan expression and say 'Yes!, Yes I Am!', maybe stare a few seconds longer and the go about my day. Still pissed, but thats just me. I won't give the satisfaction of the responce they want. Basic agreement and a 'so then what happened' kind of look. works for me. (i'm such a Bitch...)