My personal favorite for flawed reasons is Madoka because I was there for the live reactions to the infamous episode and it was magical watching everyone lose their shit. It was also my re-introduction to anime after being shamed out of it for liking sailor moon as a kid.
It gets really crazy once you get to the Chimera Ant arc. Its a really long arc but pays off big time.
Everyone mentions that as a big anti-war arc, I’m looking forward to it but so many episodes sad face.
It does some very interesting stuff with the normal shonen dynamics and the villain of the arc and a person they interact with are some of my favorite characters in anime, but yeah, it takes a long time to get through. For early stuff that feels a bit more like a deconstruction, I like viewing Hisoka and his world view as a portrayal of the shonen audience.