Complete strangers recognize you in the elevator as a bike commuter, and ask "Didn't you ride today?" when they see you, not in bike clothes or carrying your helmet or panniers.

That happend to me today...was lugging a 20 pound brick, er...laptop with me that I used at a conference. I decided to let Metro help me carry it, rather than putting it on the bike. I had some guy...I have no idea who he is...ask me why I wasn't riding today. I guess I'm known in the building!