Sorry I'm late to the thread, Sterling! I've been following along and meaning to pitch in, but I had to think about it. I'm interested in what others are saying about moderation, because I hadn't looked at it this way before.
I think you're doing great. Maybe your accidental purchase will be a watershed moment when you can examine your motivations and change your habits in a way that suits you. This week's rage and frustration could be next week's funny story.
Here's the thing. I'm a moderator, but I'm not a natural at it. I've built moderation muscles around various impulses over the years and shopping is one of them. I always have to work against its addictive power and I have a few strategies to keep myself in check.
First of all, I keep a couple of barriers in place to shopping online. I never use a credit card and I keep debit card purchases to a minimum. I can't shop in a single click because I need to jump through all the security hoops at the checkout.
Another favourite strategy is stalking high ticket items to buy in the future. If I see something I like, I have to ask myself if I want it more than the thing I'm stalking. I currently have prescription sunglasses and a new handbag in my sights.
I've also raised the bar for quality and provenance over the years, with my own version of Angie's 3P's. This has helped me walk past many an ill-considered purchase, and by now I enjoy the contents of my wardrobe more than I enjoy shopping in most places. Anything I buy has to be at least as good as what I already have.
But I still have a massive closet. I love it all, but it's all over the place. The shopping diet/fast is basically to help me focus on my future direction and edit accordingly. And after a spell of (not) shopping, right now I am actually Not Shopping.
I suppose what I'm saying is that you shouldn't take too many tips from me, because our lifestyle needs and style goals are not the same. On the other hand, you have my full support.
Keep up the good work!