[Sans just naturally carries around a fog of guilt as a result of his innate personality, more than anything to do with being an angel. He's just that lucky. Unfortunately, he seems to have caught on to the fact that Papyrus is uneasy, so he's now going out of his way to make him uncomfortable.]

Nah. Just figured you mighta made some kind of stupid deal, thinkin' you could get some cheap performance out of doin' the bidding of a genuine sociopath. But that'd be silly, right?