Feel free to create your own if ya don't like this one. :D
So.
Today has been.. a day. You fell down a mountain (Mt. Ebott, was it?) into the Underground, Where you have met a motherly goat lady, convinced her to lets you out of the Ruins, and here we are, in Snowdin.
As you walk down the path towards town, you see the 2 skeletons you had met before, Sans and Papyrus. Papyrus is at a station selling Hot Dogs(?) and Sans is over to the side, sitting on a bench with his hood up.
Papyrus: "OH, HELLO HUMAN. ARE YOU HERE FOR A HOT CAT?"
You ask Papyrus about Sans.
Papyrus: "MY BROTHER? OH, YES! HE HAS BEEN WITH ME ALL DAY. HE USUALLY STAYS AT HOME.. BUT I'M HAPPY HE HAS SOME FRESH AIR! MAYBE HE'S EXCITED BY YOUR PRESENCE! YOU SHOULD GO SAY HI!"
Alright, fair enough. You had seen Sans before, after all he was the first one you met after you left the Ruins. But he always seemed.. anxious and jittery around you. Well, more than usual.
You sit next to the lonely skeleton...
Sans: "...u-uhm..."
But it seems that you are not welcome.