Sayonara, Zetsubou-Sensei

Nozomu Itoshiki is a high school teacher so pessimistic that even the smallest of misfortunes can send him into a pit of raging despair; some of these "catastrophes" even lead to suicide attempts. _Sayonara Zetsubou Sensei_ is a satirical slice-of-life comedy set in the modern day, covering various aspects of Japanese life and culture through Nozomu and his interactions with his students: Kiri Komori, a recluse who refuses to leave the school; Abiru Kobushi, an enigma who frequently arrives to class with severe and mysterious injuries; the hyper-optimistic Kafuuka Fuura, Nozomu's polar opposite; and several other unusual girls, all of whom are just as eccentric as their teacher. Source MyAnimeList