Why does this keep happening?

Every so often someone thinks I'm gay and I have no idea why. It happened again last weekend. On Saturday night I was out to dinner with a male friend of mine. At the restaurant the waiter was being really friendly. More so than a waiter normally is. He would come by and we'd chat a little bit about the restaurant, their food, and the events they have there. As time went on I realized he was pleasant to my friend, but really focused on speaking to me. Then he touched my shoulder in a friendly way when he said something. At that point I was like, great, he thinks I'm gay and I'm being flirted with...again.
I should tell you that I've been to that restaurant before with a woman, and had that waiter, and this didn't happen. Nothing even remotely like it. The section of the restaurant we were seated in was narrow and there was really only room for one person to get by. Knowing this I let my friend go first as we were leaving. He passed by the waiter who said the usually waiter "good bye and thanks for coming". As I went by he smiled and touched my shoulder and said some similar waiter nicety to me.
When we got outside I asked my friend if he'd picked up on what happened and he was oblivious. When I pointed it out to him it was painfully obvious. I even emailed a gay friend of mine today to ask if I came off as gay at all and to ask how or why this keeps happening. He was stumped. I'd told him before that this happens and he just couldn't see it at all.
Maybe it had something to do with the fact that I picked up the whole check (it was my friend's birthday), the fact that I'm part Italian and speak with my hands. Maybe that can come off as flamboyant? I really don't know.

I have a dream...

As some of you may know I've recently started taking steps towards realizing a dream I've had since I was 15 years old; becoming a standup comedian. I've been to a few open mic nights, started writing material, and am signing up for a stand up class at Improv Boston that starts in July. Ironically there's nothing funny about this post.