I still haven't learned this lesson well enough. Code I think is near perfect always turns imperfect over time. The main corollary for me is that I can spend every waking second of my life making my code better, and I'll never be happy. I want to better figure out how to enjoy 'good enough'.
Instead, I might suggest that you enjoy making your code better and to be happy with the process rather than the result. Then every crappy piece of code is an opportunity rather than a curse.
Improving code beyond the point where it gives material benefit is not really a problem except for the fact that it deprives you of the opportunity to work on crappier code. Especially when working with new code, I find it useful to concentrate on process rather than end product. If you write tests like X and refactor like Y, how does it affect the result?
In some ways this is really freeing because you get over the fear of writing crappy code. If it's crappy, you just get to improve it. It also allows you to explore ideas and ways of doing things without worrying so much about the result. Concentrating on producing good code can often (in my experience) lead to achieving a local maxima but not does not allow you to kick out of it to achieve something better.
I was getting closer to that for many years -- enjoying the process -- until I decided to try and start a software business. All of a sudden, there's a huge downside to improving code without having a clear material benefit.
I'm with you on losing the fear of writing crappy code being freeing. At some point I realized that everyone's code including mine is crappy code, and there's no way around writing crappy code or introducing bugs. Realizing that did make me a better coder and a better manager. It let me be a bit more humble as well as empathetic to others, and led me to think more about the importance of testing.
