[ wow he sure is explaining honorifics to a lot of people today that's not something he thought he'd ever have to do but he ain't bothered ]

Ah, well, "-chan" is for someone cute or someone ya think you're close with. And "-san" is just kinda generally respectful, I guess. Like ya'd never just say someone's name to them, unless you're super close, otherwise you'd be pretty rude.

[ he considers this for a minute ]

Was it Nishitani who called ya that? Feel free ta punch him.