When people think of Goku's father in Dragon Ball, a lot of people immediately think of Bardock from the TV special and his continued appearances. The Saiyan father of Goku is to be applauded for sure, especially as a favorite character for many fans. However, when fans of the original first chapters think about whose influence made Goku into the kid he was, and the adult he is today, then they'd say that it was Grandpa Gohan. After all, despite his short appearance in the story, it is implied that Grandpa Gohan is the one who taught Goku to value life, as the core Dragon Ball.