I hate the ones that just blow up and make a loud noise. They're dangerous and, as you said
@Catsmother, they scare animals. We had a collie years ago that went into panic mode on the Fourth of July. We had to give him meds the vet prescribed for him and keep him close all night until it ended. Also, since the 9/11 terrorist attacks, unexpected loud explosions scare people in my city because New York City is a target for these depraved maniacs.
That said, I do like to view a legal, professional fireworks display that fills the night sky with beautiful colors and patterns.