Once while giving a talk at a dev conference I was heckled just after being introduced. This was over 10 years ago but it was something to the effect of "get off the stage, suit". I wasn't wearing a suit but apparently my overall look screams "sales guy"...

I was pleasantly surprised when I completed my talk and the guy who heckled me (I never even saw him) came up to me and apologized. Then again this was in Toronto so maybe the old stereotype about apologetic Canadians is more true than not!

The "shabby nerd" stereotype is a very real thing and it goes both ways.