Acting is for those of us who can't be evil or ****** or ****** or insane or wrong in life, but hold the burning need to be those things tight, locked in our souls.
It is for you, who want to witness those things, but only contained, only with the fourth wall shielding you from their heat,
And it is for us, who want to be consumed by those things but lack the desperation and the foolishness to succumb to them in the real world, where they might have consequences.