I think it can happen when you are waiting sooo long for this trip, and then suddenly you're there. It feels kinda rushed. Hard to believe it and you have to get used to it, now. Sometimes it's difficult, but after a few hours and seeing the classics characters and attractions makes you feel "home" again.
But for me yeah, no problem, I don't go to the parks the night I arrive so I have plenty time to recover the trip and telling myself "i'm here".