Now that's a good chunk that we are talking about. Azumanga Daioh, surely my all time favorite manga and anime ever (Even in terms of manga Ranma 1/2 is close tho...)
Firstly let's talk about what it Azumanga Daioh:
Azumanga Daioh is a Shonen manga written between February 1999 and June 2002 by Kiyohiko Azuma the creator of Yotsuba as well. The style of the manga is a Yonkoma which means that all gags are 4 cases long.
The manga introduces 7 main characters
Chiyo Mihama, a genius girl who has skipped so much classes that she's now in high school and she has a fuck ton of money. Since of course not everyone is perfect she sucks ass at sport, she also has inferiority complex due to her size and age.
Ayumu "Osaka" Kasuga, a transfer student who surprise surprise comes from Osaka. At first glance she may seem like a brainless idiot but throughought the manga you'll learn that she's very knowledgeablke about sutff, she just don't know how to use that knowledge. She a master of joke and overall a sweet girl who means no harm.
Sakaki (Last name Unknown ?????), Shy and introvert tomboyish girl whom everyone thinks she's though despite her being very polite in reality. She has a huge passion for cats but unfortunately they don't seem to like her back. She's the perfect alliance between intelligence and sport capabilities. ALSO SHE'S FUCKING TALL WHAT THE HELL.
Koyomi "Yomi" Mizuhara, More intelligent than Sakaki but less sporty than her (Albeit still being a pretty good sportgirl). She has troubles with diets she can be auite mischeavous at times too.
Kagura (Still no last name ?), Another sportsy tomboyish girl ? Well unlike Sakaki she's most idiotic of the bunch and she's more sociable than her as well. She takes her rivalry with her very seriously and despite seeming like an annoyance she actually likes to help.
Tomo Takino, the energetic very VERY unbearable high schooler, she's an idiotic menace, wants to be the best at sport but she's far from being the best. At least Osaka is kinnd and enjoyable but here I want to stab her with a knife each time she opens her god damn mouth GOSH SHUT UP.
Kaori "Kaorin", a bit on the side character but she has quite the importance during the anime. The lesbian of the bunch, she is MADLY in love with Sakaki and each time spent with her is a paradise, sadly she is too shy to admit her feelings.
There are other important characters such as Yukari, a prideful obnoxious teacher, Minano a sweeter but dumb P.E. teacher and Kimkura a... pedophile power ultimate ?????
In April 2002 came the animation simply titled "Azumanga Daioh, The Animation". Taking the mangas and transcribing them in television.
Now why do I recommend Azumanga Daioh ? Firstly it's very chill in nature and it's taken very slowly, some moments in the animation just has a lot of moment where there's no sounds for a good chunk of time. Nobody speaks, they move slightly, some background music can be heard but it's nothing too fancy. It's rarely a mess to understand.
Another good point that can be brought about the manga and the animation is that it's a MESS humor wise (Not speed wise or else my previous point would've been shit). I've finished rewatching the anime recently and despite my good memory there's a lot of moments where it's just impossible to predict ! They could do anything and watching the anime feels like a lucid dream, with friends we even joked that they were all dead.
Last point I would like to bring out is that this manga isn't too over the top. It talks about normal school girls without any superpower and each character can be quite relatable to yourself or someone you know.
You could know someone precocious like Chiyo (Not as precocious as her because she's 10 years old and she only get max grades in an high school class), it's not farfecthed to be empty heady and carefree like Ayumu, to be skillful but asocial like Sakaki, to bet all in the muscles and none in the brain like Tomo, to be a bit more altruistic in spite of her intelligence like Kaguya, to worry about your wieght like Koyomi or to be GAY.
The strenght of the anime isn't the quality of the animation because it is quite horrible at times to be frank, you can clearly see the lack of budget.
No the strenght of the anime is that it's believable, anyone you know could behave like them, you may have even encountered situations like these as well. You're not following the story of kids who obtains super powers and save the world. You just see normal students living a normal and the struggles coming with it and while watching it I reminisced my childhood and I became nostalgic of those times, you meet these characters, learn to love them and when their finals exams results were dropped you know that they will not likely see eachother again. And that's a perfect way of making someone sad, not by killing a loved character but just by introducing these characters, making you learn to love them and when the time fianlly has arrived for them to say goodbye simply due to life, to emphasize on their sadness. Nobody was physically hurt, nobody died, it's all just human.
That's why I love this anime and I wholheartedly recommend it to anyone.