My guy friend and I work together and we are close (not like close friends, but close as we coud be in an work environment). People at our workplace joke or think that we're dating, but we aren't and he's especially the one to explain it to them. When there's people around he won't sit with me and he keeps it profesional, but when we're alone he jokes around and plays around with me (as friends) and is more outgoing. He did it today and he was cold and brash when one of our coworkers was around, but switched immediately when he left. He doesn't want people to think we're a couple, and he has said that he doesn't see romance between us (plus he doesn't want to get involved in a work romance as it could get bad), but he has said that if we didn't work together and there was romance, he would've dated me. Lately, we've been hanging out together (he's the one who asks most of the time) and we get along well like a good team. So I'm wondering why he's so strict on it if he knows were just friends. He does have an idea that I like him (which is the reason he told me his boundaries) and I have been respectful of them, though I have not confessed. Any idea why?