Pat him on the head and tell him he's a good boy and he's fully prepared to kill for you!

This is so true, and also delightful.

Also that's way more interesting than "This person genuinely doesn't feel anything."

It really is! The possibility that Dexter might genuinely not feel anything was my biggest concern at the start of the show; it's hard for me to care about a character who doesn't care about anything. But he absolutely cares!

The numbers end up being a bit of a self-fulfilling prophecy if Dexter is working with the Machine, I feel.