One of Dragon Ball's most iconic elements is the golden-haired Super Saiyans. A powerful transformation that has turned the tide of several key battles throughout the series, the idea of 'going Super Saiyan' has led to countless imitators in the world of manga and anime. Despite how important they are though, one of their most recognizable aspects was added simply because series creator Akira Toriyama wanted to do less work.
Though referenced much earlier in the series, readers first saw the Super Saiyan form during Goku's battle with Frieza on the planet of Namek. The Super Saiyan transformation was originally supposed to be the pinnacle of power. With the power of a Super Saiyan, Goku was able to beat the tyrannical warlord who had killed his people. Super Saiyans have subsequently become ubiquitous throughout the series. Since Goku achieved the form, it would also be obtained by Gohan, Vegeta, Goten, and Trunks in the original series. The form would even become somewhat obsolete as the characters reached more powerful transformations such as Super Saiyan 2 and 3. Despite these developments though, it's the original base Super Saiyan form that is the most recognizable. Given their importance, it may be surprising that they were created out of laziness.
In 2009's Dragon Ball: Super Exciting Guide Akira Toriyama revealed some of the reasons Super Saiyans turned out the way that they did. While Goku's striking eyes were inspired by Bruce Lee's commanding presence, the hair actually has a much more hilarious reason for being golden-yellow. According to Toriyama, Super Saiyans have yellow hair entirely because it'd be easier to draw. What's important to remember is that manga is black and white, so extra time needs to be spent inking the jet-black hair of characters like Goku and Vegeta. With bright yellow hair though, Goku's Super Saiyan transformation would be quicker and easier to ink.
All of this speaks to Akira Toriyama's larger approach to Dragon Ball. While the series might be mostly remembered in the west for its incredible action, it started out as a much much sillier series. Much of Goku's childhood adventures in Dragon Ball had a, fittingly, juvenile sense of humor to them. Though the series eventually ditched that more lighthearted attitude, it's obvious that Toriyama still took things easy even as his series became increasingly serious.
Regardless of his reasoning or attitude though, no one can really fault Toriyama for trying to make inking Dragon Ball easier for his assistant. The fact that no one suspected the Super Saiyan's yellow hair was a time-saving measure until Toriyama himself pointed it out proves that he made the right call. Regardless of why they look the way they do, Dragon Ball's Super Saiyans will forever remain an influential part of manga history.