It's like this:

You have a boss. A wrinkled plus-sized brown business jacket of a man whose idea of "cutting costs" is turning the air conditioner off. If he caught on fire, you wouldn't piss on him to put him out. How do you address him? "Good morning Mr. Perkins, how are you doing today?"

You've got a war buddy. You met at boot camp, you served in the same company, he splinted your leg in the field, you're his kids' godfather. You'd kill and die for this man. How do you address him? "Ah god not this fucking asshole again."

Official formal polite language like "Thank you" and "You're welcome" is the pair of nitrile gloves I put on to handle the really noxious shit that comes my way. "w'thanks man" and "no problem" means I'm willing to handle you with my bare skin.