Abilities: Big Bang Attack, Fly, Fusion, Galet Gun, Destructo Disk, Oozaru, Zanzoken
Even though he is evil at heart, Vegeta is perhaps one of the most strong-willed characters in the series. Like Son Goku, he is extremely industrious, constantly striving to be better, but different purposes drove Vegeta's spirit. Goku fought to defend the lives and others and to challenge his limitations while Vegeta fought to satiate his bloodthirsty appetite and die hard pride, which is unwilling to accept defeat. This gradually changes throughout the series.
The primary driver of his will is Son Goku. Vegeta's defeat in his first encounter with Goku and his unwillingness to accept Goku being more powerful had constantly fuelled his strong will to continue to train himself. After seeing Goku turn into Super Saiyajin and defeating Freeza, he grew even more jealous of Goku achievements and immersed himself in intensive training. After much sweat and frustration, he finally became Super Saiyajin. He only enjoyed a fleeting moment of pride in destroying #20, before being defeated by #18.
Vegeta first catharsis occurred during Son Gohan battle with Cell. Because of his rash decision to attack Cell when he did not have the power to, had caused Gohan arm to be seriously injured when Gohan saved his life. Not only was he not even close to Cell ability, but also served as a hindrance to Gohan. That was the first time Vegeta accepted his incapabilities by making an apology to Gohan.
By the time Majin Buu appeared, what used to be a cold-hearted Vegeta changed. Right before he proceeded to sacrifice his life in an attempt to destroy Buu, he told Trunks that he cared about him and how he felt bad about giving Trunks much less attention then Trunks deserved.
During Son Goku's final battle with Majin Buu, Vegeta goes through a complete catharsis. He realized that Goku's pure and kind heart gave Goku the power that Vegeta never had. He finally realizes that the good ultimately prevails.