Max,
An interesting thread. thanks for starting it.
I too am a perfectionist, and I think one key to progressing while being happy is learning to channel that impulse. When I first switched to digital, I felt as though I had to learn everything. Every time, for example, I stumbled on a different way to sharpen, my reaction was 'OMG! I need to master that one too!' Well, no, I didn't need to.
There are certain things about which I am still very persnickety. For example, I do a lot of macro, and I needed really to put time into stacking. The basics are simple, but the details aren't, and I am still learning more. In contrast, my use of flash is fairly rudimentary, and I don't feel much pressure to make it more sophisticated. I do a lot of candids of people, and for that, I often need flash. I'm now quite comfortable with my basic setup, which is one flash, either on camera or on a bracket, often with a bounce card and a diffuser. It works fine for my purposes, so I have put off multiple-flash work and all the rest off for another day.
I still have as a goal improving my postprocessing, but I've grown accustomed to the idea that the progress will be intermittent and not terribly fast and that people will often refer to things I can't do.
Re genres: I am always open to new genres, but one really grabs my attention only infrequently. For example, I first tried night photography a few years ago and quickly got hooked. I also know what I don't do well. One genre I don't do very well is (unfortunately) landscape. I keep doing it, and my goal is to get better gradually, but I don't expect to get very far with it.
Like others who have posted, I often look at older images of mine and grimace. However, a few of my early ones still compare favorably to many of my new ones. The difference is that the good ones were much less frequent then and involved a lot more luck. For example, I think this may be one of the first half-dozen flower macros I ever took, and it is still hanging in our hallway:
So, my approach is to give myself a kick in the pants to improve gradually in the areas that matter most to me but to accept that there will always be a very long way to go.
Dan