Can Ex Lovers Really Be Friends?

At the risk of angering all parties involved, I'm going to pose this question.
I can't help but ask it on a daily basis. Is it really possible to remain friends with your ex? Well,there are a few things to consider:

How serious the relationship was, why you broke up, whether you were in love (because everyone knows love doesn't die just because a relationship ends), and finally, whether or not either people are in new relationships.

I'd like to believe genuine friendship is possible at a relationship's end. But, judging from my own personal experience, I think it's a better idea to burn all ties of communication with your ex, if you want to have a healthy emotional life after them. My ex and I dated on and off for about a year before we "officially" called it quits. Because we do attend the same school (and live in the same dorm) it was kind of hard to cut eachother off completely. As a result, since the beginning of the school year, we've been trying to turn our remains of relationship into a friendship. But it wasn't as easy as we'd thought it would be. To dig up the list I mentioned earlier:

Yes, our relationship was serious.
Yes, it was a bad break up.
Yes, we were in love.
And, yes, we had "moved on".
....well, at least one of us had.

Trying to maintain a friendship with an ex who has a new girlfriend, while you're still single, is a very bad idea. I didn't realize how jealous, possessive, and annoying I could be until I attempted to do it. Having to see pictures of them, gifts and cards from her, and actually see them together is enough to drive me up a wall. I've become ultra sensitive, extremely emotional, and I've turned into the super bitch I didn't know I could be. I take everything personally, and always assume that whenever I can't get in touch with him, it's because he's ignoring me for her...the list goes on.

Obviously there's more to the story (I'm just protecting his privacy) so I'm not as psychotic as I sound...But the point is, to avoid the emotional rollercoaster, don't try to be best friends with your ex. It's just not logical.