http://www.youtube.com/watch?v=5hfYJsQAhl0
I should point out that I did an experiment. I put two heat sources under the bull snake enclosure and I broke up the snakes. They are curled up together at the back end of the cage. My boas also curl together. They are hardly ever separated. If they hated each other, I believe the first thing they'd do is try to get away from one another, but they don't.
Here is what snakes do:
Hunt, Eat, Sleep, Defecate, Mate, and repeat. Snakes get stressed if they can't move around enough in captivity, or if they think something is a predator about to eat them. There is no psychology I know of about snakes hating one another. I believe there are some species of snakes which are more aggressive than others, but I do not think they hate other snakes or get too stressed out in captivity because they are in one cage. I don't believe they care. If the snakes were too stressed out then they would likely show it by trying to find a way out all the time but they don't.