Here's the all time classic
https://www.youtube.com/watch?v=T_lh5fR4DMA
The real science
http://www.scientificamerican.com/article/men-and-women-cant-be-just-friends/
My personal experience from yesterday
When I saw the title I thought: Haha, I just experienced this yesterday.
Over the last month a girl (ENFJ likely) has tried to get IN my life. She texted me. She wants to meet up all the time.
I was really surprised. Why would she be so interested in me?
Well, she already has a boyfriend and just wants to be friends.
When we had our first 'date' yesterday (not earlier due to logistical stuff), she mentioned her boyfriend (I already knew, but was confused). I continued to tell her what my perspective was. She felt really sorry and didn't see it that way. This happened when we were walking to the café. We didn't turn around actually. We just talked about it. About things she did and why I think it's a signal of interest and why she thinks it's just her trying to be friends. She felt really sorry for all of it and was really nice. We had a lovely time for the rest. I haven't felt really bad or sad about it (yet). I feel slightly empty, but I have enough other stuff in my life to pay attention to I guess. She really wanted to meet up again sometime, because she really does want to friends. I agreed to it, but not anytime soon, so I'm sure I don't 'catch the feels'.
She assumed I already knew she had a boyfriend from the beginning. So she never backed down or tried to be less touchy or in-my-face.
So yeah, we're going to try to be friends. I can think of two things (there are probably more) that are beneficial to such a friendship.
1) Not being single
If both parties aren't single, their desires are fulfilled (mostly the guys' ones I guess) and they won't play a role in the friendship
2) Maturity
Knowing that you should/want/need to be just friends and being mature/disciplined enough to not try more, will prevent the friendship from leading to more. Again especially on the male side.
I fail the first one, but I'll try the second one.