The villains and heroes in his movies think the way kids do. If you defeat the neighborhood bad guy, of course all crime would stop. If you're a rich guy, of course you'd turn your entire wealth into diamonds. Who wouldn't want diamonds?
The violence in his movies is also never really sinister. Nor are the villains - especially the thugs-for-hire cannon fodder - ever truly evil. In Rumble in the Bronx, the initial bad guy - Tony (iirc) - becomes Jackie's friend once he realizes that Jackie is actually a good guy.
That's child logic, and I absolutely love it.
I know some "serious" movie critics fault his movies for their simplistic plot lines, but to me, this is a feature, not a flaw.
Outside of animation, I don't see any western movie maker doing anything remotely similar.