Two specific bad endings from Club Suicide (yes, I know, it's in the title of the VN but still)
One of Shiki Kururugi the one where he dies in the arms of the MC was horrible, after drinking poison to commit suicide he lies in her lap and starts agonizing oh no, oh no...
One of Masaya Usui this one felt like a betrayal, I had to get it with a walkthrough and it was listed as a bad ending, but everything was happiness and rainbows and even the happy ending ost started playing, I was like well maybe he won't die and then he goes and gets ran over by a truck while saving a child. Why they played the happy ost? WHY???/ISPOILER]