Tourguide, you brought up some VERY good points. And explained "what is normal" quite well. Better than I had ever heard it explained, I must say.

What I find interesting is that many of the same people that judge (in the vanilla and the BDSM community) seem to ignore one simple and basic fact. It is a fact that thrill and excitement (whether it comes from pain or pleasure) give off the same biological responses. So, our behavior (be it as extreme as it may get) shouldn't really be that shocking. The vanillas ride rollercoasters and go to scary movies, we simply merge our adrenaline rushes and excitement into our sexual experiences. We all need release. Humans aren't built for the mundane. Even the most average persons who have the most mundane lives are constantly searching for an outlet. Their outlet are videogames, sports (extreme sports, even, now), movies, shooting ranges, all sorts of things. Ours outlets just happen to be sexual in nature but the result is very similar. It releases something inside you (the animal, the beast... the natural chemicals for certain) that needs to get the "rush" from the thrill. We all need it. We just go about it different ways.