The one reason people hate Dragonball Z is all the stuff Funimation did to make it cool. It had all those pointless, long, drawn out fight scenes, which were present in the Japanese version (obviously) but it got rid of Toriyama's little touches that made it such a classic of the late 80's/early 90's anime. FUNi's music was way too serious, and the dub voices didn't match the Japanese seiyuu at all.
Case in point: Vegita sounded like a cocky prince in the Japanese version, but the dub gave us the most horrid deliverly of a line ever. "OVER 9000!!!" His dub voice sound like someone scratched their throat with sand paper.
Dragon Ball's earlier seasons were awesome, since Toriyama brought over a number of factors from his previous series, Dr. Slump (which I haven't read yet, I heard it's funny).