White coats aren't "mandatory" per say... But they're something you should wear. If you don't wear it because you're coming into a hospital or had to go to an emergency, that's fine. However, as a medical student or intern, it can come across as arrogant or lazy. Arrogant because you feel like you're better than the rules. Lazy because you couldn't do the one thing you should do. I'm not talking about one time ordeals, either.
I don't have a problem with it. My problem is certain hospitals condemning you if you don't wear a tie 100%. I like wearing them and I almost always do, but I get livid when I forget to wear a tie one day and an attending has to remind me of it. Like, Jesus ****ing christ, I know I forgot it. I already feel bad. Don't lecture me.
But he still did.