This moment
Vegeta was doing brilliant until the cyborgs came. Should have made him the main villain after Freeza - he trains, reachs SSJ and goes on to fight Goku on a rematch - only then should they become friends. This way they ruined what could have been the best character in all od anime because they lazy and dont have imagination.
But still, Vegeta >>>>>> Nappa >>>>>> Goku