I have.

A few years ago, I was set to present an award for gay literature at an event hosted by the group LAMBDA. I patiently waited over two hours for my category to come up, then finally straggled to the podium, half dead but still willing. "Hey, guys..." I started, and was greeted by a loud round of boos. I had forgotten that in a mixed crowd, you don't say "guys"! I'm such a stupid...person!