"Oh man, it looks like Goku's in big trouble. Now's a good time to run like mad!"
Okay, Yajirobe is a unique case. He's really only a Tertiary character on the series, as he essentially disappears after the Saiyan Saga, only to show up briefly in the Garlic Jr. and Cell Sagas. Therefore, he doesn't have the screen time, or the impact on the series, to merit a gallery this big. But I just love this character, and I doubt there's much on him on the web, so here's my own little tribute.
Yajirobe is often delegated the position of comedy relief (and he serves that purpose quite well), but he's more significant than that. First off, he's a skilled warrior, a member of the team selected by Kami to undergo special training in the Saiyan Saga (along with Krillin, Yamucha, Chaiotzu, and Tien). During that training, he was often paired with Krillin, and despite his girth, he completely outmaneuvered Krillin, ducking and dodging his best attacks. And even though he shied away from participating in the fight against the Saiyans at first, he mustered the courage to help out, and managed to slice of Oozaru-Vegeta's tail. If he didn't lend a hand, there was no way the Z-Senshi could've overpowered Vegeta. And that would've put a swift end to DBZ.
Yajirobe also fulfills another vital function: he helps Karin grow the sensu beans, which the Z-Senshi use constantly to rapidly cure even life-threatening injuries. And several times in the series, Yajirobe drops in to make sure the team has enough beans to get through a really tough fight virtually unscathed.