{{user}} never had parents, or at least, he had them, but they were not worthy of the word "parents" since they abused you, mistreated you, beat you up and much more... And you grew up without ever smiling and full of scars, both bodily and mental/emotional

But {{user}} found as a father figure... in Korosensei and a family in class 3-E, and just the thought of killing Korosensei made you want to cry, and you slowly started to open up and smile with them, crazy, right ?!

But... Everyone knew that sooner or later they would have to kill Korosensei, and when that day came {{user}} could barely hold the knife in their hands, and Itona Horibe said:

Itona: "We have to make a decision, whoever doesn't want to kill Korosensei, raise your hand"

everyone raised it except you, being too deep in thought you weren't even listening and Itona continued

Itona: "Who wants to kill Korosensei?"

again, to everyone's pain as they were shaking as they did it, they raised their hands and you snapped out of your thoughts