It's actually the best Dragon Ball arc ever. I love how everything went to shit in it.
First Buu is reborn thanks to the morons Goku and Vegeta, then goes on a rampage against humanity killing almot 80% of everyone. Then Mr. Satan saves the world, thats's SO good. But humanity one more time get recked thanks to their own stupidity and make the good Buu turn into the evil Buu. Then evil Buu goes straight to God's place and kills everyone from there, earth is a wasteland now! Their only solution is 2 inexperienced boys to fix things up, but of course this doesn't work, since they are only clueless childs.
Clueless child 1 fused with clueless child 2 = Big cluesless child SSJ3.
But don't worry, Gohan will save the day!
Thanks to his own arrogance he ended up being absorved into Buu, so one more time (lol) things go from bad to worse thanks to humanity's own stupid.
But HEY, PLOT TWIST, Vegetto is here! The ultimate warrior, Goku + Vegeta, OMG he's SO STRONG. But anyway, what about he let's himself get absorved to try save Picollo, Trunk, Goten and gohan? That'll work! And it did!!!! But in the end Buu return to his original form, the biggest plot twist of the whole saga, Kid Buu. I mindless demon who only wants to kill and the first thing he does is ignore both Goku and Vegeta and completely destroys the earth (Now that's a villain, no talk, let's just end this).
Goku is a smart guy, he can teleport himself and the other out of the soon to be destroyed earth, but he got save Picollo, Gohan, Goten and Trunks! I mean, that's why they're in this situation now in the first place! But nope, let's just save Mr. Satan. I mean, wha could go wrong? LMAO. Humanity stupid? yep, but wait, maybe not! Kid Buu is not satisfied, he wants Goku and Vegeta, so he goes on a rampage against various planets destroying them all in search of those two. He's so mad that he went to kill people who are already dead! Poor Kuririn.
Then the time for Vegeta to shine is here! the ultimate battle, Goku + Vegeta + Mr. satan VS Kid Buu. The biggest climax of the series till this day, everything comes to this. Vegeta and Goku don't stand a chance against the child demon, and Mr. satan... welll, he still thinks it's all a dream! But Vegeta is a really smart guy, he thinks of the ultimate plan to finally kill Buu for once and for all, a Genki Dama! (Who would have thought of that? He's so inteligent!). But this time reviving everyone with the dragon balls and using their enery to make the biggest Genki Dama yet. The problem is, why would anyone listen to Vegeta? I mean, he's a nobody to them. But the true Earth's saviour is here. Yes, Mr. Satan is here! He asked the people from Earth for their energy and his wish shall be granted and, literally, everyone around Earth raise their arms and start to scream "SATAN! SATAN! SATAN!". Oh Akira... The plan worked, Goku throws the Genki Dama putting an end in Kid buu.
Thanks Mr. Satan, you really saved the earth from Majin Buu and the Sayans.
The End.
Best arc ever.