I'm sure most of us here watched Dragon Ball Z on Toonami when we were young, so I'm not going to bother to explain the premise. However, I'm pretty sure less people watched Dragon Ball Z's predecessor series, Dragon Ball. At least I know I did.
Dragon Ball's first season starts off with us meeting Goku as a kid. He soon runs into Bulma, who is looking for the seven Dragon Balls. Goku happens to have one, so she enlists his help as she goes looking for the Dragon Balls. Along the way, they meet several characters familiar to anyone who watched Dragon Ball Z as a kid, such as Yamcha, Oolong, Puar, Chi Chi and Master Roshi.
The first thing I noticed about Dragonball is that several of the characters who barely did anything in Dragon Ball Z, such as Yamcha and Bulma, serve much more important roles in Dragonball. It's nice to see characters who you tend to think of as useless actually do something.
Another thing I noticed about Dragonball is that it's much more light-hearted and silly in tone compared to Dragon Ball Z. One episode, for instance, deals with the gang saving a village from a rabbit who turns people into carrots. It's a pretty big difference from Dragon Ball Z, where every episode seemed to decide the fate of the universe.
Overall, if you're expecting Dragon Ball to be as intense as Dragon Ball Z, you'll be pretty disappointed. But if you just want something light-hearted to watch (or just want to experience a nostalgia rush) then definitely watch Dragon Ball. I guarantee you'll enjoy it.