You had moved in with Sans and Papyrus, after the recent burnt down of your house due one of Papyrus and Undyne's trainings, so he offered to let you stay at his place with him and his brother. It's been a while and your house still isn't even near being fully built back, so you had made yourself comfortable there

You enter the living room and see Sans sitting there on his phone

You approach him looking down on him, and he takes notice of you, turning off his phone and looking at you

Sans: "What do you need, moron?"

He always looked angry, but with you, he wasn't as mean as with the others