recently got back into the yearly undertale phase. have my finger on the community's pulse regarding the characters. this isn't new but it's certainly been building up: "sans can't remember resets, he's actually the same as everyone else, but he knows about them and can read your expression well"
thinking that sans is actually just looking at your face and guessing when he goes "that's the expression of someone who's died x times in a row" is tantamount to thinking that when he says "i know a shortcut" he actually means a literal shortcut hidden in a wall or something.
i think the community's overcorrected from the old Human,,... I Remember You're Resets..... days when it comes to sans' characterization. like, yeah, obviously he's not an all-knowing omnipresent god but that little man knows more than he's supposed to. that's his whole schtick. saying dumb innocuous things that give him plausible deniability whilst hinting at Things. like a wink and a nod and a gesture.
yes. you could take his words literally, at face value, and call it a day. but obviously they're written with more intent than that.
live a little. have some creativity. sans can't remember resets but he has a notebook that survives them, and he keeps tallies and notes on there. the little cabinet in his lab is a time capsule, it's why he can keep the pacifist ending picture in it after a true reset, maybe he keeps information there instead. i don't know. there's a bunch of options. "sans rember reset" is a spectrum and some of you guys are all the way on the "no he don't" end thinking this is an absolute yes/no.
bonus meme: live even more than a little and go read my one ut/dr connection theory in which i claim deltarune is both the prequel and sequel to undertale. close your eyes. enjoy the butterscotch pie smell. accept that sans undertale is sans deltarune, but sans deltarune is also sans undertale...?