Tear Jerker / Sayonara, Zetsubou-Sensei

  • Even the normally over-the-top ridiculous Sayonara, Zetsubou-Sensei has one of these in Episode 11 of the second TV series, when the girls sadly explain what has driven them to murderous insanity. "But... he never chose any of us."
    • The ending of Episode 11 is bad enough, as it moves completely away from the usual wacky and over-the-top tone. That's his entire class waiting for him outside the operating room. And if that isn't tearjerker-y enough for you, here's this AMV/parody ending.
      However, in the next episode, he's just fine.
  • The author's Heroic Self-Deprecation. Be sure to read his notes at the ends of volumes.
    I think I'm creepy. I just can't stand any part of myself. If I went to a picnic and saw my ugly face reflected in the lake, I'd just jump into it. If I went shopping and saw my ugly figure reflected in the show window, I'd bang my head against the glass and cut my throat with a fragment. My TV is always on. That's because if I turned it off, I'd see my ugly reflection. On sunny days, I have no desire to leave the house. Even my shadow is ugly. I'm an ugly manga child who'll never see the day when I become a swan. I changed the lightbulb over my sink to the lowest wattage.
  • The second-to-last chapter of the manga reveals that Kafuka is Dead All Along. Even worse, the last chapter reveals that her friends will eventually forget about her.
    • Upon reaching this twist, the three opening songs that Kenji Ohtsuki performs for the anime start to become Harsher in Hindsight and come across as being rather painful when you take the lyrics in mind. Ringo Mogire Beam, in particular, hammers it with the chorus referring to how the persona thinks it's "Shangri-La" and "paradise" being with the person they love.

      Iím sitting up! Already,
      Weíre twisting, twisting, twisting away
      Make it so I canít tell why Iím trembling!
      Slipping away! Iím already a twisted human
      But if I meet you, I can change, right?
      (Just realize that I am here)]]
      ——Hito Toshite Jiku ga Bureteiru

      Címon, run around trying to escape during that gap
      Dance the real rumba
      To have a light smile with youó
      That day will come
      (I believe in it rumba)
      ——Kuusou Rumba

      I swear itís Shangri-La if Iím with you
      Our password
      (Apple plucking beam!)
      Over there
      Over the slight side of despair
      (Come over here!)
      I swear itís paradise, we can do it
      Our password
      (Apple plucking beam!)
      —— Ringo Mogire Beam
http://tvtropes.org/pmwiki/pmwiki.php/TearJerker/SayonaraZetsubouSensei