Most of the biggest problems in the Dragon Ball universe have been caused by Vegeta...
Dragon Ball Z is one of the most iconic anime series out there. It follows the adventures of Son Goku and friends as he saves the earth, the galaxy, and the universe from the clutches of evil. However, poor Goku has his work cut out for him most of the time, as were it not for his best frienemey Vegeta, the universe probably wouldn't need as much saving.
Here are the top times we slapped our hands to our foreheads and said "Why, Vegeta, why?"
When he killed Nappa for no reason.
Vegeta, along with his buddies Nappa and Radditz discover that they are the last living members of their race: the Saiyans, following a death-ball related genocide. Naturally, they want to bolster their ranks up, you know, rebuild the population. So, they head to Earth to recruit Goku, who is also secretly a Saiyan. Goku and Piccolo promptly kill the scout, Radditz, forcing Vegeta and Nappa to get their hands dirty. However, when Nappa looses a single battle, Vegeta decides that he is no longer worthy of his life, and blasts him to oblivion. Way to ensure the extinction of the race you are so proud of, bro.
PS: As a bonus, when Nappa is brought back to life in Dragon Ball GT, Vegeta kills him again!