Only reason the spirit bomb didn't kill Frieza was because all the Namekians were dead plus the planet Namek was dying so Goku could only squeeze enough energy to form a mediocre spirit bomb.It worked against Buu.
Almost worked against Freeza...granted, he got up from it, but he was fukked up and angry after he got hit.
To answer the thread's question, Goku's biggest weakness was that he loved to fight and get stronger... but not to kill. Sad part was that Vegeta, Gohan, Piccolo, Future Trunks, and even Tien had the killer instinct and drive to destroy their opponents but they were no where near as strong as Goku to get the job done so everybody suffered because of it.

Chi-Chi is the reason he's ultra smart. Before piccolo took gohan, he had no training at all cuz goku was too scared of chi-chi to teach him.
That nikka Goku couldn't read, he thought "marriage" was a type of food and Chi Chi was like "
This dumbass nikka is dumb enough to put up with my shyt!"


"Nah, bruh...you gotta die NOW."
"A challenge!"

Goku.
. Vegeta stayed true to his roots, that's just who he is. If I just found out I went SS I'd want the baddest MF i can find to test my strength. I'll take that L but at least I'll know my limits. 



I DON'T KNOW WHY YOU COMING DOWN HERE, MESSING WITH THESE PEOPLE!"
and