The Dragon Ball franchise has gone on long enough that several key characters have grown up and had children. One such character is Vegeta. It's safe to say that fans never expected this from the sadistic Saiyan prince, especially after his ruthless invasion of Earth and disgust for the heroes. Lo and behold, however, he eventually settled down with Bulma and had a child, Trunks.
As weird as it sounds, Vegeta's son comes in two varieties. One comes from an apocalyptic future ruled by androids, and the other grows up in the peaceful present. (Yes, Dragon Ball throws in time travel at points.) Neither version of the son is as mighty as his father, but each one possesses certain traits and skills that Vegeta doesn't have. Knowing him, that's much to his chagrin.
7 Eliminate A Threat Immediately
This is a problem with Saiyans. They love battle and thus like to draw it out as long as possible. In Vegeta's case, he taunts his opponent and flaunts his superior strength. This often gives villains a chance to transform or pull some dirty trick out of their hats.
Having grown up in an oppressive future under the thumb of such villains, the Trunks of the Android Saga takes no chances. He makes that clear the minute he dispatches Frieza. Upon returning to his time with his newfound power, he immediately engages the cybernetic sadists and reduces them to scrap in minutes. The same goes for Cell. Trunks knows this insectoid android will flee the first chance he gets to consume more victims, so he swiftly vaporizes the parasitic freak. One has to admire a hero this responsible.
6 Have A Non-Confrontational Romance
Another area where Future Trunks cuts the nonsense is romance. He eventually gets involved with Mai, who has moved on from serving Emperor Pilaf and now fights alongside the resistance. She acts as Trunks's rock, offering emotional support and aiding him in any way she can. In return, he loves her immensely. What's more, he's not afraid to show it.
Contrast that with Vegeta. His marriage to Bulma isn't exactly a smooth union. They both have extremely dominating personalities, so they fight all the time. Granted, this is part of the attraction, since they challenge each other. They're also capable of being intimate when it counts. Still, it's understandable why everyone is initially shocked at their pairing.
5 Be Friends Instead Of Friendly Rivals
The Trunks of the present day may have had a different upbringing than his post-apocalyptic counterpart, but he has the same noncompetitive attitude. In fact, he's best friends with Goku's youngest son and fellow Saiyan, Goten. Sure, they go at it on certain occasions such as martial arts tournaments, but they spend far more time just having fun. They love nothing more than getting in trouble together.
Goku and Vegeta's friendship isn't as openly wholesome. Though they're also in each other's company a lot, they mostly spend it trying to outdo each other. That's not to say they don't have fun; they just convey it through friendly jabs. Someone always has to get the last word. At times, they act more like children than their sons.
4 Do The Fusion Dance Consistently
The Dragon Ball franchise has demonstrated many ways to combine bodies and make one ultimate warrior, but this particular ritual is rather ridiculous. It involves a bunch of flamboyant moves straight out of Power Rangers (or the Ginyu Force), which must be performed with absolute precision and synchronicity. That said, maybe you can't teach an old dog new tricks.
Goten and Trunks are two of the silliest, most juvenile characters in the roster. Such a stupid dance might come more naturally. Of course, it also helps that they get in a ton of practice. Now, the kids have it down pat and can fuse into Gotenks anytime. They often break out this technique at the start of a fight.
Goku and Vegeta have never been able to emulate that ease of access. Whether in or out of canon, they've always used fusion as a last resort. Even then, it takes them several tries to get it right. True Saiyans fight alone, after all.
3 Reach Super Saiyan At A Younger Age
This goes for both versions. When Future Trunks transforms into a Super Saiyan, he's only a teenager. This surprises everyone, especially since they thought Goku was the only one. Moreover, it really gets under Vegeta's skin. At least it softens a similar blow years later.
The Saiyan prince is training with Present Trunks, who's only eight years old. To compensate for the intense gravity, the kid goes Super Saiyan. Both of these instances leave Vegeta speechless. He himself didn't achieve this legendary transformation until he was well into adulthood.
2 Run A Company
Despite its worldwide success, Capsule Corp is a family business. Bulma naturally takes over from her parents and carries the company to new heights of innovation and renown. Vegeta never wants any part of it even after marrying into the family. He mostly secludes himself in a gravity room and trains. Thus, his son is next in line.
Fans see this in Dragon Ball GT. Here, Trunks is the president of Capsule Corp. He may not like the job — he skips out every chance he gets — but viewers never get any indication of the company's downturn or failure. On the contrary, it seems to be doing pretty well. This shows a managerial prowess on Trunks's part that Vegeta never bothered with.
1 Heal People
This is exclusive to the Dragon Ball Super manga. After vanquishing Cell and the androids, Future Trunks has to contend with Majin Buu. He prepares for this battle by training under the Supreme Kai, who was impressed by the warrior's altruism. Unbeknownst to Trunks, this gives him the aility to heal people's wounds. He unconsciously keeps Mai alive several times using this gift, and later harnesses it during the final battle with Zamasu.
Suffice it to say, Vegeta rarely demonstrates this kind of nobility, least of all to the Supreme Kai. He doesn't even like the self-righteous little twerp. The Saiyan prince can heal people later, but this is due to the Spirit Fission technique he learns on Yardrat. This involves sapping energy from one target and distributing it to another. Trunks's method drains only himself, complementing his selfless nature.