In "Contractor's Routine" we get to see Jacob's fantasies. These fantasies control him, so to speak, for a short period of time. I think it's safe to say we've all been there; pulling into your driveway and you think "I don't even remember getting off the freeway". But how much do our fantasies, or day dreams, have an impact on our actions? And is that impact positive or negative?
In the movie we get to see Jacob's reactions to this thoughts and fantasies and they put him in an irked state, causing him to find a way to take out his frustrations. I find my self wondering if his fantasies are a result of his conscious thoughts or if it's the other way around. The human mind is so difficult to understand, especially when it's the mind of someone who his slightly (or greatly) disturbed. You can't get into someone else's head, you can only make assumptions and create judgments/biases from that.
Jacob struggles to control his actions through the help of his conscious because he knows that these thoughts he has are wrong. Everyone has committed some act that they know was wrong, it's human nature to make a mistake. However, it's the aftermath; the remorse, the conscious effects and how we shape our actions thereafter that have a real say in whether we are mentally stable. What I find scary is that you can think you know someone for so long and they will end up doing something that shocks you. It could be betraying your trust or robbing a bank, but it makes you realize that you have no idea what it going through some one's head. It could even be something that you've done and after the fact you are so ashamed. All in all, who knows? I say don't be quick to judge because it could have been you.