in Dragon ball Z it was said once every 1000 Years, a super saiyan was born. Kakorat was born, with broly at the same day, they were both super saiyans. then vegeta was a super saiyan, and gohan, and trunks and goten, and then we have 6 super saiyans. and they were all born in a distance of under 100 years. somehow, kakorat becomes a super saiyan 3 for an inco-fucking-herant reason. Piccolo is able to get like a super form, how does that happen. the six super saiyans, are are all born in under 100 years, but a super saiyan is born once every 1000 FUCKING YEARS so this is why anime is full of bullshit.
