These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Tear Jerker: There are many, many really nice moments capable of causing a welling up for nice reasons. But, then, there's also stuff like Shou's sudden death, or Hikaru's spiral toward death in the closing episodes - particularly as you have to watch her spend her chance at survival in order to participate in the final battle.
As someone put it in Figure17's entry on the Anime/Tearjerker page: 'Try watching the ending credits after all this, and watch as what was once cheesy becomes heartbreaking.'