This happened a few months back and it's not very great, but to me- it was. I was standing in Walmart. Just standing there, in front of the rest rooms, minding my business. Some guy walked straight up to me and said 'I LOVE your shirt!'. It happened to be a Buffy shirt.
Considering my friends never watched Buffy and in my entire shool life I had only met 1 person who watched it (and this chick was so obsessed it scared even me) I was shocked. No offense meant to any guys here, but I was super shocked that it was a guy gushing about my Buffy shirt.
Another time, wearing the same shirt, I was buying something at a DVD store when the clerk (another guy) said 'OMG I love Buffy!' Then continued to talk randomly about Buffy until I was done swiping my credit card. (I would have stayed to chat with him, but the line of people behind was LONG)
I wear the shirt as often as possible, hoping to find more Buffy fans in my area.