The greatest High School anime might be debatable in your mind, but in mine, it can't be anything other than Cromartie High School, which is an absurdist anime about a high school for delinquents or yankii. It is a high school of endlessly tough young men, including a robot who doesn't know he's a robot, a gorilla and Freddy Mercury. (oh and read the manga).
Takashi Kamayama is the protagonist and every episode's narrative structure is centered around his shocked letters to his mother. He was a young man who was always on the straight and narrow, called "The Errand Boy" in High School, until he committed an crime in junior high. While he initially tries to fit in and act tough, he soon realizes his duty is to reform this group of genuine badasses. And he's accepted as one badass bunny. This anime follows one magical year of crystalline brilliance and growth. Or just one year where a bunch of weird shit happen to a group of remarkably stupid people. Depending on your perspective.
Pros of this manga:
It's consistently hilarious, though I do admit whenever I show my friends, they seem confused. I also have a friend whom likes exactly the opposite types of anime that I do and he hates this particular series. I have no idea why. I suspect he hates rainbows and kittens and everything good in the world.
Ok, but what are the pros—it relies on 15 minute episodes with a fairly tight narrative structure. It has Mechazawa, a thoughtful delinquent robot and leader of a band of toughs. And shockingly, no one realizes that he's a robot. It also is very good about having episodes about absolutely nothing, like episode 3 which is partly about how they can't remember the name of a particular tune. But it can also riff off of classic tropes, like father and son alienation in Gorilla Sushi, though there is some banana sushi involved. You just need to watch to truly understand.
Takashi with his friend, Shinjiro Hayashida, tries to do the right thing but invariably gets caught into rivalries. For example Takashi, under the guise of Honeyboy, constantly beats out the head tough at a rival high school by sending in the funniest postcard into the local late night radio show.Now, for the average series, it might be a amusing little pastiche of a story but for Cromartie, it becomes a drama of Shakespearean proportions. And that's why Cromartie is funny.Like when favorite show of the boys, Pootan, a show of sullen men in bear costume, is one of the better shows within a show and becomes even more highly charged when Freddie joins as a character. It not only is absurdist and exaggerated, it focuses largely on the smallest and most mundane of details for its comedy—while often having weirdly unlikely plot twists as well.
And in the end, mother, this anime teaches you how to be a genuine badass delinquent and now I will be calling myself, "The Kinjatator" because I can take down all you motherfuckers with one click of my keyboard.
Cons of this Anime:
There is some offensive language and such things, but they are badass delinquents, so I suppose they aren't well known for their ability to choose their words, so it's narrative consistency. Also, if you are looking for character growth or a moral center, this is the wrong anime for you.
In conclusion, watch it, WATCH IT NOW! I have all the DVDs but you probably can watch it on youtube, or something.