I will never understand this trope. A name is a name, why be so embarrassed by it?
It's degrees of closeness.
Last name with legit, big boy honorific is like "Sir Chief CEO Master Lord Anderson". -sama, -dono, etc.
Then it's last name with normal or hierarchical honorific, for acquaintances, office mates. Mr. Anderson. Here's your senpais, sensei.
Then it's last name, "standard" honorific. -san, -kun, -chan. This puts you as basically equals in a personal sense. I feel like this distinction isn't really held for western senses, since I think this is where you just drop honorifics or start using first name.
Then its friendly, like forgoing honorifics or putting some stink on their last name. Anderbro, 'cause he's your bro.
AND THEN you use their given/first name. Because you're personally interested in them, beyond familiarity. Calling someone like this in public is a giant "we're dating and we've gone beyond h*lding h*nds" sign. After that is pet names and all that shit because you're soooo lovey-dovey.