@JWChibi
It probably all starts when the character realizes that it is in a fictitious world written by someone else. For example, in the world of the cultivator the protagonist realized how the magic system was absolutely incapable of sustaining itself, perhaps Su Luxia realized, when she was in her original world, how everything was too absurd and instead of following the normal rules (of society, of common sense, sometimes even physical) was all aimed at carrying on a story, and how she – and everyone like her – were just abattoir to exalt only two people in the world (protagonist and ML).
If you don’t join the system you disappear, or you’re forced back into your corrupt world. One of the basic concepts of transdimensional travel in these stories is that you MUST overcome missions positively, because if you fail you are not only punished with a salary drop or a note of demerit but you are just killed.
Rejecting them in principle is like condemning oneself to death.