Sometimes I go to change code to do a new thing and it is easy to do. The new cases fit in, the existing system doesn't explode, all is good. Sometimes the cod

Sometimes I go to change code to do a new thing and it is easy to do. The new cases fit in, the existing system doesn't explode, all is good. Sometimes the code is beautifully factored and tested. Maybe even documented. It then proceeds to fight against the new change. Maybe the type invariants fail everywhere for reasons that price spurious. Maybe code far away makes dubious assumptions and breaks in response. In the worst case, it's beautiful nonsense held up by undefined behaviour and the language has come to collect the tax. I like code that can be changed to do new stuff without everything around it exploding. That's probably what I'd call good code. It's in the context of tolerating future requirements well as the future is now. I do not see such code often.