I was just thinking the same thing the other day. I was going for the course stamps by beating all the non-DLC staff ghosts, and my first try through Water Park looked really promising... Until I saw the top scores, and that gap was much wider than I thought it would be. Still, better than the vast majority! ... Which probably mostly includes young children. Yaaaaay skills.
Haha, I keep wondering how come staff ghosts are actually beating the majority of players. I mean, those staff ghosts are awful!