A Dead Giveaway

I had a cab driver the other night who was the chatty sort (as opposed to the talk radio sort, or the cellphone sort, or the eerily silent sort). As we waited in a traffic snarl near the Queensboro he asked me what I did for a living, but before I could answer he said "Wait, don't tell me - computers, right? Internet?" I asked him how he knew, and he replied "Your glasses! Nice girl like you wearing those glasses, all those black clothes - it's always something with computers."