To me it sounds almost like what I refer to as the face I wear for the outside world. That Mike never gets angry, is quick witted, quick to make a joke, and in general seems like a pretty happy guy. He's usually around when I am around other people, even though he feels like he doesn't totally "fit in" either. Then there is the dark Mike, he can sit for days in the blackest of depression and literally not have a single word come out of his mouth. He is quick to anger and incredibly slow to calm, he hates everything and everyone around him. He has no sympathy for anyone but himself and feels that life has just cheated him and no one understands that about him. He is the guy that would suggest firing someone with small children they are trying to take care of because they've been late for work a few times. He's callous and mean. Both are me and I have to accept that I believe to move on. I don't think you have multiple personalities (I am not expert mind you), but from what I understand people with multiple personality disorder don't even know about their other personalities. I used to be able to snap back and forth the way you do, until too many stresses just cracked that mask and made it unwearable anymore. Now I am just trying to rectify the two men into one whole healthy man.