In the annals of Dragon Ball history, one of the entries will certainly be written about the rivalry between Goku And Vegetable are their personal differences. Historians would write that Goku is the kind, easygoing, and friendly branch of the duo, while Vegeta would be written off as the annoying, obnoxious, and opinionated opposite branch. While there is a reason for these classifications, they are not entirely accurate. At times, Goku has shown himself to be everything the villain Vegeta was at first, at least in terms of disrespecting his peers.
In one particular instance, Goku's indifference caused great harm to Vegeta, who had previously served as Earth's champion and protector in Goku's absence. This incident occurred in Dragon Ball Z Volume #169, Chapter #391 of the manga, marking Goku's return to the world after training in the Hyperbolic Time Chamber. Prior to this, Vegeta had replaced Goku as the planet's protector.
Goku tells Vegeta straight up that he's falling behind.
Goku showed unusual indifference in this situation.
After defeating Cell with all his might, Vegeta's pride is hurt when his son Trunks becomes Cell's formidable opponent. However, any feelings of inferiority towards Trunks are overshadowed when Goku and Gohan leave the Hyperbolic Time Chamber ahead of schedule. After assessing Perfect Cell's strength, Goku admits that he is no match for the monster, but also refuses to spend any more time training in the Chamber. When Vegeta mocks him for fearing the harshness of the space, Goku responds with the most vicious insult he can muster:
“However, I have no opinion on your use of this room. Perhaps you still have a lot to improve on.”
When Vegeta angrily asks if Goku means he's improved more than him, Kakarot simply replies “Uh-huh. A lot” before flying off with Gohan, not even giving Vegeta time to reply.
The relationship between Goku and Vegeta fortunately changed after that insult.
Goku's statement implies that even though he spent less time training in the Chamber than Vegeta, he still reached a level of superiority. Goku's insensitive and unnecessary comment shattered Vegeta's pride.especially considering his recent attempts to fight Cell with only the help of his son. Goku's reaction is unwarranted, and this exchange offers a rare glimpse into Goku's evil nature.
Things got worse when Vegeta retrained in the Hyperbolic Time Chamber, he was still weaker than Gohan and Goku, as shown by his poor performance in the Cell Games. However, after witnessing Goku fight Cell, Vegeta accepts that Goku is a better fighter.With his rival gone, Vegeta can finally find peace as a husband and father, in a world that no longer needs his power to protect.
However, his newfound calm and resilience crumble when he discovers that, even in the afterlife, Goku has continued to train and improve, and has surpassed him even further, reaching Super Saiyan 3. This revelation explodes Vegeta's frustration and causes his progress to fall apart. Ultimately, this causes Vegeta to succumb to Babidi's influence and eventually become Majin Vegeta.
Fortunately, during the Majin Buu crisis, Goku and Vegeta reconciled once again, fighting together to save the universe. Dragon Ball Super did a lot to further develop Goku and Vegeta's relationship, showing Vegeta as an equal on the same power level rather than an eternally unmatchable rival. However, that harsh comment was made by Goku Before the Cell Games always stood out as one of the worst humiliations Vegetable have received in Dragon Ball history.
