During Dragon Ball Z's classic Cell Games saga, a self-proclaimed "hero" arrived on the scene, much to the annoyance of the Z Fighters. The showboating braggart Hercule Satan claimed to have defeated Cell, taking all the credit for Gohan's victory while downplaying Goku and his allies' valiance and sacrifices. While this self-serving lie was entirely selfish in nature, Hercule inadvertently ended up helping the series' true heroes.
Hercule's 'Heroism' In Dragon Ball
Hercule was always an incredibly hedonistic, arrogant and boastful fighter in Dragon Ball Z. He became the Worlds Martial Arts Tournament champion at a time where many of the combatants weren't particularly impressive, as Goku and the others were often busy with their own lives or battling villains on other planets. Cashing in on his success and fame in the fighting ring, Hercule claims the Z Fighters are his students and that he singlehandedly beat Cell with one move.
This served to make Hercule even richer and more famous than before, a feeling and lifestyle he easily took to. His wife would actually leave him due to his sleeping with many different women, with his renown only making him buy further into his own false hype. Thus, it's hard to see him as a particularly good guy, but these actions did end up helping Gohan, Vegeta and the rest of the Z fighters in a big way.
How Hercule Helped the Z Fighters
As mentioned, Hercule promptly rode the wave of media adoration after claiming credit for Cell's defeat, being viewed as a cross between a superhero and a movie star. The actual heroes' actions were completely looked over and passed by unmentioned, and thus their lives, besides having lost Goku, were unaffected. In other words, life went on -- potentially for the better.
Many of the Z Fighters' actions between the Cell and Buu sagas may have been impossible if they'd been caught up in the popularity Hercule so easily embraced. For one, Chi-Chi was adamant that Gohan would become a student and focus more on his academic pursuits than fighting. He successfully gets into and attends high school, achieving a level of normalcy his father never did. This scenario likely wouldn't have been possible if he'd been revealed as the true defeater of Cell, as he would've been hounded by reporters and various other hangers-on.
Some of the others, meanwhile, also focused on non-martial pursuits. Vegeta officially settled down with Bulma while Krillin married and started a family with Android 18. These new domestic developments were all a result of the peaceful times experienced after Cell's destruction, and part of this was afforded by Hercule taking the credit. As seen later in Dragon Ball Super, the seeds planted in the aftermath of the Cell Games bloomed into Gohan attending college and becoming a professional academic, even speaking at conferences. Their extended lives of peace and prosperity would have never been possible without Hercule's "sacrifice" years before.