As much as it pains me to say it, I think that movies like "Kazaam" need to exist because they help support the argument that you don't ALWAYS have to see a movie to know that it will suck.
A popular defense by fans of a particular film is "well, since you haven't seen it, you don't know what you're talking about." And in many cases, this is correct. If someone who had never seen Pulp Fiction, The Dark Knight or Fight Club tried to tell me that they weren't going to bother seeing any of those films because they think they will suck, I would pull out my toolbox and nail their ass to a chair just to make them sit through those films and form an educated opinion.
However, you don't need to watch 5 minutes of a crapfest like Kazaam to know that it is utter dogsh**. You can... and if you want to waste a couple hours of my life be my guest... but if you ask me, this movie is only useful in the following conversation:
"Hey, man, have you seen Step Brothers yet?"
"No... Not going to bother. Looks like crap."
"But you haven't seen it! How do you know it will be bad?"
"I didn't see Kazaam either, and I know that movie sucked."