Something my family has learned to be of immense importance in terms of any family outing or vacation is being very careful with our expectations. And now, even for the simplest day trip, we discuss everyone's expectations ahead of time.
A.) It allows you to know ahead of time if everyone's ideas of a fun time don't align.
B.) It helps to go over your plan out loud and ask yourself if you're being realistic.
It sounds like maybe your expectations weren't terribly realistic---like maybe you were hoping the Magic of Disney would enthrall your kids enough to stop some of their very common, very typical, very age appropriate tendencies such as squabbling with one another, impatience in line, etc. We find our kids have *more* behavior issues when they are incredibly excited---leading up to a birthday or Christmas, and on vacation. It's like they've used up all of their patience anticipating the holiday or event and when the big day/week/trip arrives, they have empty tanks!
Even now, when my kids are older,we still try to remind them in advance of the things that will happen that they won't love, and to have plans A,B,&C in our minds for dealing with those things. Because even big kids can get impatient or grumpy if they get too tired or the waits start being consistently long.
We've definitely been there, done that, and all you can do is try to learn from it for next time. I'm sorry it put a damper on things for you.
Better luck next time!!
(I know we have stories, but I'm drawing a blank on any particular ones right now. I will say, though, that DS #1 went through a phase where the types of things he might eat in the parks---fries, nuggets, soda---"special treats" in other words, would randomly make him immediately sick...like puking all over the ground or once even while we were still in the restaurant! That phase was a real joy, let me tell you. Ugh! Because, of course, this is the kids who adores trying new foods and eating out. Now, my youngest--stomach of steel, but hates everything. "Have kids!" they said. "It'll be fun!", they said.
)