I rarely regret just getting things done. Excessive planning is a much larger issue. I find it's usually better to just do something twice rather than spend too much time thinking about it.
One absolutely fantastic upside for just getting it done is that even if you have to redo it from scratch, you have so much better real-world understanding of the problem space.
I'm inclined to think that this applies to majority of the things we do, but is often brought up regarding building products in the idea that one should build the first prototype quickly, just to be scrapped so the final solution can be built from clean slate, benefiting from all the knowledge the prototype helped us gather.
Most often, in my experience at least, the knowledge one gains from actually doing the thing (even badly) surpasses anything that could have been gained with excessive planning. To actually work, genuine effort including some planning is definitely needed, but I don't think that's too high a bar. At least not when compared to the skills and knowledge one would have needed to achieve the same success with "just" excessive planning up front.
What the books taught me was how to write clearly, if with a somewhat unorthodox style. Turns out that's extremely important for a software engineer.
If my childhood had more books and boredom I might have the patience to spend longer in the planning stage and less enthusiasm for the drinking coffee and pounding out a solution stage.