Because it's an internal conflict. You don't just go POOF! and it goes away. If you do then you're not there yet. it comes. The anger phase happens because escape velocity must be much faster/stronger than normal cruising speed once you get some objectivity. Then when you're above it things get so distant and you wonder how you got sucked in. Being angry is a natural reaction. After awhile it goes away - especially if during that time you develop a new foundation that more befits your new person. Now I see it as you say, but occasionally they will sucker me into hating them again until I can feel the distance again. How we are raised has a tremendous impact on who we are later in life. It's not an easy conflict to resolve. Professionally we call it "cognitive dissonance".