Most Devs I've met have been rational, so I'm fortunate enough to not have had a fight with a dev.

There was, however, one guy. Had to collaborate with him on a web app. I would fight with him almost everyday to not use deprecated tags, use proper CSS, not hack something together because it just works and the list goes on too long.

But I never succeeded in convincing him. Learnt that no matter how much you try, you cannot convince someone stupid