Goku beats him at the Martial Arts Tournament, and then he's like "I'll get revenge for my father" and doesn't do anything for 5 years? They were pretty on par at the tourney, you'd think he'd have tried something. Hell at the time he was evil and he knew Goku was going to get married, he could have attacked Chi Chi or an infant Gohan to get revenge. Also, I had no idea Gohan was only 4 at the start of the Saiyan saga. I thought he was 8ish *shrug*.
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