Somewhere, somewhen, we, as software developers, started thinking that other programmers would rather extend code rather than modify it. This has led us to write code that tries to predict the use cases of future programmers and to pre-emptively include mechanisms for them to use or extend our code. And because it has seeped so deeply into our culture, if we don't do this -- engage in this theater -- we get called out for not being good software engineers.

Of course, the extra hooks we put in to allow re-use and extensibility usually results in code that is slower and more complex than the simple thing. Worse, very often, when a customer needs a new feature, the current extension hooks did not predict this use case and are useless, and so the code has to be modified anyway, but now it's made 10x more difficult because of the extra complexity and because we feel that we have to respect the original design and not rip out all the complexity.

I like Knuth's quote [1] on this subject:

> I also must confess to a strong bias against the fashion for reusable code. To me, “re-editable code” is much, much better than an untouchable black box or toolkit. I could go on and on about this. If you’re totally convinced that reusable code is wonderful, I probably won’t be able to sway you anyway, but you’ll never convince me that reusable code isn’t mostly a menace.

[1] https://blog.jj5.net/blog/2021/05/21/knuth-on-reusable-code/