I see an effect used in some games : your character has a value (or something), but if they sacrifice it or go against it, they gain temporary dramatic superpowers. For instance, Buying off a Key in The Shadow of yesterday, or Challenging a value in Smallville.
For me it creates something (climax to a character-arch) with a tool that is not adequate (because there is no arch). Of course, it works, but I see many cases where it is forceful. It works fine to foreshadow and reveal a secret ID, because the gradation, the arc is self evident, but it is forceful when the coward suddenly becomes a brave, because foreshadowing here is broken, there is no arch, so no climax, so why super powers ?
I don't like this mechanic but this is not my point : I want to know it. What have I missed ? What does it do that I didn't see ? and most of all, I'd like to know the culture around it : how did it come to be ? did the function or the use evolve ?