When we went to Disneyland a few years ago and it seems like me and my wife spent more time in the park than the kids did. They spent a lot of time at the hotel and got more enjoyment out of the pool. Its kind of disappointing that they didn't enjoy it as much as we did.
I went with no expectation, since it was his first time I really thought it could be a disaster. I think each time you go back it gets better and better, especially as they get older and can really appreciate it all.