Hmmm. No really terrible ones, to be honest. Even the one who was genuinely nuts had a good heart and opened me up in a lot of ways, so no real villains.
Surprisingly, after I consider it, the worst one (as far as being a somewhat "bad" person) would probably be a gal named Debra. Not outright evil or anything, but a bit of a self-centered, emotionally insecure woman who enjoyed punishing me in subtle ways throughout our relationship. Oddly enough, this was a long-running thing that even led to an engagement. (Yeah, I was a real fool.)
How about your WORST date ever?