Absolutely EVERY song from the Japan-only PS2 game, Bobobo-bo Bo-bobo: Hajike Matsuri, in which you fight off enemies with your nose hair to the beat. Yes, it's a MUSIC GAME based on the Bobobo franchise and it rocks. Hearforyourself.
Better On Dvd: Despite the fact that the S'more Entertainment box sets completely lack any subtitles whatsoever making watching the Japanese version a pain, they do have all the episodes completely uncut in English with all of the scenes that were either cut for being too risqué or time constraints on Toonami intact.
Big-Lipped Alligator Moment: The entire series is like this, but one incident stands out: during the fight in Z-block base, Beauty suddenly snapped and started going along with the series insanity, scaring the crap out of Heppokomaru. Eventually, when Bobobo and Don Patch finally got back into the screen, she went back to normal. This was never mentioned again, nor did it ever happen again.
Pickles, who appears in the first chapter and is not fondly liked by Bobobo. He topped a Supporting Characters character poll.
And in Shinsetsu, we have Namero and Pokomi, the former an eternally stoic Deadpan Snarkerwho eventually becomes the newest emperor of the Neo Maruhage Empire, the latter being a lolita-bait, bubbly magical girl and Gasser/Heppokomaru's younger sister.
Rice. He's in about four episodes, and yet is insanely popular in the fandom.
We also have Jelly Jiggler. Originally appeared once in the beginning for a joke, but was liked so much he become a Breakout Character and an Arc Villain, then pulled a HeelFace Turn and became one of the show's main trio.
Gunkan/Captain Battleship, despite being shafted after his defeat, he's very much significant in the anime as he's promoted into more significance into Greater-Scope Villain categories with his presence more apparent, added to the first opening's character roster and even the Big Bad of the PS2 video game. Being voiced by Ryuzaburo Otomo/Paul St. Peter helps.
Evil Is Cool: Battleship, OVER, Halekulani, J, Hanpen, Hydrate, etc....
Moral Event Horizon: Bi-bibi is the one who caused the Hair Hunt in the Hair Kingdom because Bo-bobo was about to become the next king! Later in the battle, he used his true power, Kegari Shinken (Fist of Hair Hunt), to pluck out the Hair Balls out of Be-bebe, Bu-bubu, and Hatenko; and Bo-bobo engages him in a sword duel while protecting them. However, Bu-bubu's Hair Ball was broken when Bi-bibi stabs it and she dies. Then Bi-bibi took this opportunity and stabs Bo-bobo in the body, destroying the Hair Ball and killing him. But Bo-bobo came Back from the Dead thanks to Landmine Dandy replacing his Hair Ball with the Landmine Ball and defeats Bi-bibi with the help of the power from his allies. After Bi-bibi is defeated, he is spared because despite his evil ways, he's actually a good father to his daughters.
Sequelitis: Many fans on both sides of the pond find Shinsetsu Bobobo-bo Bo-bobo to have this for various reasons. Sadly, this plays out when Sawai was forced to end the manga after 73 chapters due to demand from Shonen Jump's staff and loss of interest from fans in general.
Stupid Sexy Flanders: Almost anytime Don Patch dresses up like a woman. The most noticeable example is when he dresses up as Beauty in the first opening.
Tastes Like Diabetes: In Den-bo(-chan)'s first appearance, she sings really cutesy songs, and in her second appearance, she is reading aloud a strange childrens book she wrote.
Tear Jerker: Despite its comedy, there are some genuinely sad scenes.
Jelly Jiggler (Tennosuke Tokoro in the Japanese)'s backstory of being laid off for not being sold.