Most off the time you think you are listening to the Angel on your shoulder. But then later on you find out the Devil on the other shoulder was just a hell of a ventriloquist. amirite?

So did he tie up the angel and knock him out? Why doesn't the angel say anything?

sometimes he does (example: angel-"its wrong!" Devil-"but everyone else is doing it") and I guess if you focus to hard on what the devil is saying you don't even notice the angel talking!