A defining feature of Dragon Ball Z was directly inspired by Bruce Lee

Akira Toriyama explained how Bruce Lee's powerful gaze inspired Goku's look in an interview for Dragon Ball Z guide translated by Kanzenshuu:

"His eyes right after he first transformed and looked up at Frieza... I based Bruce Lee's."

Akira Toriyama, like any good mangaka, pays attention to detail. At the time of the manga's original publication, Goku's very first transformation was a big deal. The phrase "Super Saiyan" had yet to become the historic Shonen moment it is today. So when it came to first designing the new form of Goku he would use to defeat Frieza in a climactic battle, he had to make it perfect. This includes the look in Goku's eyes.

"Since that look from his [Bruce Lee] where he's staring at you is chilling! That's what I wanted to do in the Frieza arc...Once Goku gave that look , as far as I was concerned the story arc was over."

Akira Toriyama was inspired only by the best. There's something poetic about one of cinema's most iconic fighters being a direct inspiration to one of Shonen's most popular protagonists. Inspiration is a testament to Lee as a timeless character whose on-screen presence continues to inspire creators to this day.