The only neighbor noise I noticed was out on the veranda and I certainly don't begrudge happy families playing and laughing together on vacation. I did notice some hall noise, but no more than should be expected with that many excited people tucked into close quarters with one another (many of them children). I did hear door slams occasionally and even slammed a few myself. Closing a door isn't something one usually has to think about so it's easy to be distracted by the all the magic as you pass through your door and suddenly "SLAM" (oops).
The bottom line is that the noise ranges from minimal to reasonable with an occasional "oops". If you can let it go, enjoy yourself, and let others do the same it's no problem. If you truly need silence or seclusion to recharge on vacation, you probably already decided against a cruise and booked a cabin in the woods instead.
Disney folks tend to be generous of spirit, courtious and understanding. So enjoy your pixie dust and rest assured you'll get a good night's sleep in your stateroom.