This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Silent Ponyville Chronicles
The Bad+ ending of "Darkness Scoots" Rainbow Dash saying her final goodbyes to Scootaloo after she dies and apologizing for not be there enough is the most tear inducing thing you'll ever read. If you don't find it saddening you have no soul.