In the Beginning Was the Word, and the Word Was Suck: A Guide to Truenamers

[willpell]

Note to willpell this is only possible because in 3.5 and pathfinder the game explicitly allows you to voluntarily fail your save. Thus it is take as truth that a saving throw even a will save represents some form of conscious effort to resist.

It can't possibly be a conscious effort to resist, because if someone casts a Charm on you and you fail the save, you don't know that you made one. It must be reflexive, automatically triggered by the targeting of your mind with hostile magic; it's essentially an immune system, and while you might be able to do things like intentionally exposing yourself to more germs, you can't actually make yourself succumb to a disease. Your body won't allow it, and the same goes for Will saves - they're autonomic defenses with which your non-conscious components will protect the whole of your self even from you.