Its everything, it's the fact that there are limits to what you can do, even thought there are height limits there are no age limits, an adult can run up to mickey mouse and give him a hug and feel like a 5 yr old and people watching, old or young, get that feeling of joy that it brings. Only in Disney does that happen, in the parks nothing outside matters, all your troubles and worries are left at the entrance, all you want to do is go to the next shop, watch the next show, ride the next ride or decide where to eat or just simply sit down, breathe in and wait for the moment to hit you that you really are there at last