One useful lesson I've learned in Al-Anon, is to stop flogging a dead horse. If twenty zillion times of saying the same thing hasn't had the desired effect, why would I imagine that the twenty-zillion-and-first time would?
I can say what I need to say to reset a boundary, or, if asked, impart information, but I can stop to question my motives, and if I'm trying to control, then I need to let it go, put it down, close my mouth, walk away, just give it up.
I had one of those moments of illumination last night, and in the past, I'd have tried to share that with the alcoholic. Forcibly, if necessary, with a raised voice and angry tone. But I've learned the very valuable lesson that if the stove is hot, don't put my hand down on the burner just to check and make absolutely sure that it's as hot as it looks. If every other time I've tried to express my feelings about the way I'm treated, I've been met with disdain and dismissal, why would I think this time will be different? If the burner is red, the stove is hot. Keep my hands in my pockets.