Why the Very Concept of Male-Female Friendship Makes People Uncomfortable (Slate)

It was famously said in the movie, When Harry Met Sally:

Harry Burns: You realize of course that we could never be friends.
Sally Albright: Why not?
Harry Burns: What I’m saying is – and this is not a come-on in any way, shape or form – is that men and women can’t be friends because the sex part always gets in the way.
Sally Albright: That’s not true. I have a number of men friends and there is no sex involved.
Harry Burns: No you don’t.
[…]
Sally Albright: How do you know?
Harry Burns: Because no man can be friends with a woman that he finds attractive. He always wants to have sex with her.
Sally Albright: So, you’re saying that a man can be friends with a woman he finds unattractive?
Harry Burns: No. You pretty much want to nail ’em too.

I found the above to be a little confounding because I’ve had equally enjoyable friendships with both genders. Apparently Juliet is just as confused as I am.

via Why the very concept of male-female friendship makes people uncomfortable. – By Juliet Lapidos – Slate Magazine.