I just remembered one! This one wasn't really awkward in person but later on I felt awkward after thinking about it.
So, my friend and I were on line for AnimeNorth 2012 pre reg tickets on Thursday. There was a guy in front of us that we made small talk to. Well, while we were talking, a FF 13-2 Sareh walked by and the guy said, "You know, I never understood the phenomena of girls wearing less clothes in cosplay than they do in their daily lives."
My friend and I agreed with him. It was only later, after my friend and I got our badge that I realized that I was one of those girls. ._.