I guess maybe I'm older (was in my twenties back in 1999-2001), and now I do just think they're kind of dumb. I mean, I'm sure there will be one or two that are actually pretty cool, but overall it just isn't that professional.
I remember the old Barry Sanders line that he never celebrated a touchdown because he was just doing his job. If every time I finished a successful day of work (I have a pretty public facing job) I jumped around and whooped and hollered and made a big fuss, people wouldn't take me very seriously.