Cast:
Developer A, a younger developer who is recognized company-wide as an expert in the latest features of blb++.
Developer B, an older developer who maintains widely used legacy code in blb++ involved in about 80% of a billion dollar multinational's profits.
Dev A: Your group should change the coding style in this application to the new standard.
Dev B: Sure. But since we don't have good Unit Test coverage in this area, we shouldn't just go in and do it by hand. I need to guarantee correctness. I've done a change this big before using a syntax driven automated code rewrite tool, and one can guarantee correctness if the code structure allows it. If you know of such a tool for blb++, you can help me out and we can do it.
(Background for the reader: No such tool exists for blb++ which can guarantee correctness. Such tools do exist for other languages in Dev B's work experience.)
Later on, Dev A is grousing about how Dev B is just coming up with esoteric excuses to do nothing. She's kind of put off. Dev B is put off, because he's kind of been accused of making stuff up, even though he's talking from a particularly interesting and valuable part of his work experience.
Dev A is correct, in that the new coding style is better, more efficient, and would even prevent mistakes going forwards. Dev B is correct, in that he really needs to guarantee correctness, especially if he's going to make a change that big which has no visible benefit to stakeholders. What's the takeaway?