I was fortunate enough to have Azumanga Daioh be my first slice of life anime I've ever watched. The kicker? I watched it over a decade past its original release date. So when it comes to my scoring of it's art and sound design, I've adjusted accordingly.
Everything about this anime is hilarious and adorable. The characters are all pretty unique, they each have their own archetype forming a diverse, yet cohesive group. The humor is silly and a lot of times relatable.
I've watched the anime back in... ~2013 and rewatched it last year.
It's just THAT good.
This anime has gotten me hooked on the "slice of life" genre.