For me, I feel the birth is such an exciting moment no matter what, that I don't need the extra surprise. I'm sure I'll end up surprised by something anyhow. With DD, I ended up "surprised" by a 36+ hour labor.
Not knowing something just stresses me out anyway. I'd rather not spend my entire 9 months obsessing over the unknown. Part of that is just due to my personality. I have some control issues. I don't like not knowing something knowable, and I like to be prepared. Obviously, less anxious people, people with more laid back personalities, may feel very differently.
Totally get you. I wasn't really responding to the folks like you who know they want to know. I was responding to Munchkin, BeanBean and Katie, who were all saying they didn't really want to know but felt like maybe they should find out in case they're disappointed. I was offering a point of view that might help them come to a conclusion.