Of course, not only comedy genius, Azumanga is also a brilliant slice of life, with its well-established characters that is surprisingly so human that you could really connect with them. They're also topped off by the fact they're so full of colorful personalities, which makes you love em even more. I could not get enough of how much of a dumbass Osaka is, how hyperactive and loud Tomo is, Sakaki's cool demeanor accompanied by her extremely soft side, Chiyo's intelligence accompanied by her childlike nature and innocence, Kagura's tomboy nature, Kaori being so down bad, and Yomi, the only one to put a sense of normalcy into the show, and even some of the teachers and unmentioned side characters. They're all contributing to make this show so endearing, not to mention endearingly funny too. You can't help but fell in love with these characters.
The way it builds up and progresses, you feel like you really get to see this characters grow, and other than being hilarious as hell, I think that's also the best part about Azumanga Daioh. The series really makes you feel like you're making a friend, you're watching that friend grows, and eventually say goodbye to them as they need to move up in life, and go to college after you both graduated. I think it's amazing that this series could that exact feelings.
Favorite Episodes (in no particular order):
Yamamayaa
Graduation Ceremony
Culture Fest, Second Year
School Trip
