Transmigrating is a good thing if you didn't have a happy life before it, or if you transmigrate after death. Either way, it brings a second chance, a second life!
But... what if you already had a decent life before transmigrating, only to end up in the body of a wanted bandit who escaped from prison and is forced to flee from place to place? And what if you arrive in a dark age with backward technology, a feudal system, and all kinds of cultists and twisted monsters for reasons unknown? That kind of transmigration absolutely cannot be called a good thing.
Obviously, this is a Darkest Dungeon fanfic.