Does anyone here think they're particularly good at introspection or modeling themselves, or have a method for training up these skills? It seems like it would be really useful to understand more about the true causes of my behavior, so I can figure out what conditions lead to me being good and what conditions lead to me behaving poorly, and then deliberately set up good conditions. But whenever I try to analyze my behavior, I just hit a brick wall---it all just feels like I chose to do what I did out of my magical free will. Which doesn't explain anything.

My suggestion is focussing your introspection on working out what you really want. That is, keep investigating what you really want until such time as the phrase 'me behaving poorly' and 'being good' sound like something that is in a foreign language, that you can understand only by translating.

You may be thinking "clearly something has gone horribly wrong with my brain" but your brain is thinking "Something is clearly wrong with my consciousness. It is trying to make me do all this crazy shit. Like the sort of stuff we're supposed to pretend we want because that is what people 'Should' want. Consciousnesses are the kind of things that go around believing in God and sexual fidelity. That's why I'm in charge, not him. But now he's thinking he's clever and is going to find ways to manipulate me into compliance. F@#@ that s#!$. Who does he think he is?"

When trying to work effectively with people empathy is critical. You need to be able to understand what they want and be able to work with each other for mutual benefit. Use the same principle with yourself. Once your brain believes you actually know what it (ie. you) want and are on approximately the same page it may well start trusting you and not feel obliged to thwart your influence. Then you can find a compromise that allows you to get that 'simple thing' you want without your instincts feeling that some other priority has been threatened.