My sister is such a pain in the ass

I can't believe like out of the blue my elder sister was being rude to me, i' m just so pissed. But, i' m gonna have a family dinner tonight and i certainly do not want to ruin it.
the story goes like this,
It was my turn to have a shower when my sister was done, and i found that outside the washroom door was really wet and i supposed she was the one who did it.
and i went like, "sis, why is it so wet?",
and can you guess how she replied?
she simply said "Well, clean it up!"
and i was like so shocked!
i'm just sooo pissed!! Grrrr~~