Remember that scene in Quest For Fire when the more socially advanced primordials teach the protagonist to do it missionary style?
I think that's where the human race went wrong. I find the very idea of looking at someone when you're having sex with them very disturbing.
I mean, some things are just too private to share. It's, it's almost like you're sharing the moment. Very unsettling, I say.
Of course, this is just one man's opinion.