IIT Kharagpur: Why do we indulge in self-harm?

The following is an excerpt from a samvaad (dialogue) session with Acharya Prashant.

Questioner (Q): In spite of being fully aware of the consequences, why do people engage in self-harming behavior? Why do people stay in toxic marriages, relationships, friendships, get into addictions, do substance abuse, or get into other miscellaneous self-harming activities?