Goku is naive, forgetful, and cheery. He's seven years old, and has never interacted with a single human being, aside from his grandfather. As such, he can't remember names very well and just makes up something vaguely similar, usually an item of food or drink (O-lon becomes Oolong, Olaf becomes Pilaf, etc.). He doesn't know anything about civilisation, so things like cars and the opposite sex are completely alien concepts to him. If Goku knows one thing, it's how to fight, though, so his first response to a situation is typically violence, although over time he quickly learns to ask first before fighting.