Anyway, something that was an enormous help to me was to kind of give myself permission to stop in the middle. I'd get all worked up, arguing, yelling, and at the same time there would be this little voice in my head saying "noooooo! this isn't what I wanted to happen!" but I didn't feel like I could actually stop out of... I don't even know, some misperception that I shouldn't, that I should finish what I started or be consistent or something. Those kinds of messages about what "good parenting" was were getting in the way. Ironically. Some of it, too, was a kind of fear of looking like a fool - stopping and saying "okay, woah, I'm totally off base here, can we start over?" just felt... embarrassing. I didn't want to admit I'd gotten it wrong.
It turned out that a big part of learning to be a better parent, a gentler, more thoughtful parent, involved admitting I got things wrong, or wasn't sure what was right, on a fairly regular basis. Fortunately - and much to my chagrin - my kids had never actually been fooled by my bluster And they appreciated my backtracking and apologizing. Part of Me getting there involved being okay with my own inadequacy, being gentle with my own humanity.
The next thing that helped was asking myself "why the heck not?" whatever it was my kid wanted - because usually those arguments involved a kid wanting to do something (or stop something) and me insisting on doing things the way I'd imagined them playing out in my mind. Recognizing that things didn't have to go that way, that I could say yes a whole lot more without ruining my kids for life, made a lot of things easier. More than that, recognizing that "being consistent" didn't work the way I thought it did, freed me up to realize that it was okay to Try Things, just this once. To experiment and see what happened, then review things with my kids and figure out what worked and what didn't. And mostly, nothing "worked" in the sense of once-and-for-all solutions - that's what's wrong with the whole idea of "consistency" to begin with. Because situations change with a million different factors it was actually more "consistent" to problem-solve each time than to apply some generic rule that didn't always make sense, or needed a hundred caveats and exceptions.
Once I got used to stopping in the middle and changing course, it was easier to do that earlier in the process. And over time that meant I was asking myself the necessary questions and doing the problem solving before things got fraught in the first place. It didn't happen over night, and sadly my older kid got the brunt of my process, but in the longer run I think it made him gentler with his own process, more accepting of his own humanity.