The problem with these people is that 90% of everybody believes that DragonBallZ "came out" when the anime started airing in the US.
DragonBallZ ENDED in early 1996. 8 years ago was when the Buu season -ended.-
DragonBallZ and Sailor Moon are the only animes (Well, besides Sazae-san and Chibi Maruko chan) that a gigantic % of the population watched.
Anime isn't mainstream in Japan, most people don't watch it. Most people read manga, though.
Anyway, the point is--DBZ and Sailormoon, while not as highly revered today, at least in the US, set the stage for almost every anime you sit here smirking and consider to be "better."
Almost every energy attack you see in any anime, is emulated after what Toriyama Akira envisioned.
People who say it's a "recycled plot" and it's "repetitive," they definitely were not at the time. DBZ and SM had the biggest anime followings in Japan's history (again, besides Sazae-san and Chibi Maruko-chan, which aren't really anime--they're just animated shows).
DBZ was fresh, it was new, and people were excited to see every episode.
That's why it's respected, even though by TODAY's standards, the plot-type is old.
People compare Naruto to DBZ all the time. What sense does that make? Naruto is less than two years old. DBZ came out more than 10 YEARS ago, more then half of most of your lifetimes.
There's no reason to HATE DBZ, because even if you don't like it as much as some other animes, you can be sure if it's an action anime it took example in many ways from DBZ.
Sorry for rambling, but I hope at least one more person understands why DBZ, while not the best anime, should be respected nonetheless.