Adults can be worse then teeenagers. I think you'll find rude people in any theme park.
This past week I was in the WWoHP listening to the Hogwarts Frog Chior. I was in the front to the left side of the circle. I was standing there taking picture when all of the sudden I felt something on my legs. An adult women had just crawled on her hands and knees between my legs to get in front of me. She never said excuse me but instead got up and stood right in front of me. I was appalled and speechless.