Goku points out how Vegeta practically used The Power of Love to momentarily surpass even him, after Bills slaps Bulma.
To put this in perspective, Vegeta getting beaten to near-death and generally being used as a chewtoy by Kid Buu—likely the greatest humiliation he's ever endured—never pushed him that far. Lay a hand on Bulma, and Vegeta summons up enough berserker fury to deliver a flawless twenty-second beatdown to a being who could defeat him with a halfhearted finger poke. Say what you will about Vegeta, but don't ever touch his family.
The fact that the writers let fan favorite Vegeta have that moment after he's been stuck in Butt MonkeyCan't Catch Up land for so long. And after the bingo dance.
It also shows how far he's come from the callous world-murderer of his Planet Trade Organization days, which in and of itself is another layer of heartwarming.
Gohan's reaction when Videl reveals to everyone that she's pregnant with Pan.
Beers respecting Goku enough to spare Earth in the end after he teaches him to let go of his pride and admit that he can't win.