because গোকু has patience to supress his powers like gohan when he was a kid but when গোকু gets angry he gets angry Vegeta the same but Vegeta is always like that Trunks is like গোকু too But trunks can't achieve UI with no God Training Vegeta didn't surpass Beerus at FP yet because he doesn't have patience and can't just stand there when someone is about to attack him, but গোকু has surpassed his patience and been late EVERY SINGLE SAGA so he has a lot of patience and defense not like vegeta who is just offense
