Virtually everybody except Goku was eventually killed off, forgotten, fodderized, demoted to extra or turned into a jobber. so many great characters, wasted.

"This planet is going to explode in five minutes!!!" Cue the same characters fighting for another ten whole episodes before the planet finally blows up.

A lot of the juciest potential bits of character development were skipped over entirely just for the sake of getting to MOAR fighting. We already know Goku's going to reach the next level of Super Saiyan-ness and punch the villain of the week's lights out. How about an episode that deals with the effects of Goku's horrible fatherhood and abandonment of his son? How would he battle that?

(Not to mention all of the other characters like Gohan and Krillin who had interesting character arcs that were mostly glossed over or left mostly unresolved.)

Pointless filler. Some episodes are all filler. This makes the series as a whole very poorly paced. Admittedly this was because Akira Toriyama was still writing the manga as the show was on the air, but it's still annoying.

If you manage to survive an arc you join the team. Tien, Yamcha, Piccolo, Vegeta, Android 18, Majin Buu TWICE. I know Goku's a good influence but c'mon.