I talked about this in my recent Virginia report when I rode I305 for the first time. It's rare that I ever get an adrenaline rush out of fear anymore, save for a handful of rides on my first go - Kingda Ka, Dragster, Skyrush, I305. But even then its not really fear, its more of... intimidation that I'm about to do something that has a reputation for being completely crazy. I know its going to be fun, and I try to focus on that but all I have to go on are what other people have told me about the ride. But after I do it once, all that goes out the window and I just enjoy it (or hate it) for what it is.