When Goku defeats an entire army single handed, you didn't think there was much left for him to take on.
However King Piccolo and his demon children were more than trouble to Goku and his friends.
After Goku puts his children 6 feet under King Piccolo gets pissed.
After beating Goku, he gets the Dragon Balls and wishes for his youth. He also destroys the fucking wish granting dragon. Badass.
The fight between him and Goku was epic.
Such a great finishing move too.
Then you learn the whole Kami bullshit.