This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Celestial Warrior Moon
The tears begin as early as Chapter 2. When The Rake makes his move, it begins in the basement where Naru's mother and two exterminators she hired to take care of the house's rodent problem are looking for the fuse box after the power goes out. They're suddenly attacked in the dark by The Rake. We never see what happened, but the gist of it is that while The Rake was killed one exterminator, but the other managed to grab Naru's unconscious mother and make a dash for the stairs carrying her to safety with him. He'd just made it up the stairs with her before getting dragged back down into the darkness by The Rake. We never learn this man's name, but it's impossible not feel for him when his simple act of kindness to a woman he didn't even know got rewarded with his imminent murder. In fact, that we never learn his name arguably makes it worse.
Usagi tries to save Crane Game Joe whom she presumably knew for several years, after he was turned into Entomon of the Great Youma. Luna tries to stop her because she (Luna) doesn't have the things needed to heal him on hand, and wants to kill him, not caring that this is someone innocent that Usagi knows. While they're arguing backup arrives and teleports him away. Luna slaps Usagi, who also has to deal with the fact that someone she knows got killed because of her (in her mind). Worse, seeing what happened after Entomon escaped Luna may have been right after all.