I used to think that the IC world and consistency trumped OOC considerations, that actions should always have APPROPRIATE consequences (emphasis oldme's), that things need to not be realistic (because lol magic), but SENSIBLE. Sensible was absolutely a requirement in every way.
I've totally given that up in favor of #1 priority being 'everyone enjoying themselves' -- it doesn't always work, and sometimes there are conflicting goals and things, but I think it's a better approach to the hobby than IC being sacrosanct like I used to feel.
It really is OK to have your bloodthirsty monster of a character NOT be a bloodthirsty monster if the other person isn't going to enjoy that. That's a change in the last 5 years or so for me.