Erroneously believed I was in the house alone, so I intended to have a lazy day lounging around in my underwear

.
So there I am, cooking pancakes in my underwear and my roommate walks in. If he had reacted normally it would have just been a weird embarrassing thing that everyone goes through, not noteworthy enough for a post here.
But he didn't. No
"oh shit I'm sorry" or
"what the fuck is wrong with you why are you making pancakes half naked?" or
"OH MY GAWD *faints*."
He giggled and walked away. Like a little schoolgirl "tee-hee-hee" giggle and fucked off to his room.
Now I'm sat here in my room brooding. Thinking "what the fuck is so funny about me in my underwear motherfucker."