A tigercat's occasional waking moments

Do girl cats go outside the litter box when they're mad?

I think Biko-cat has a problem. Last night she peed on the loveseat in Daddy's study and today she pooped on the mat in front of our litter box.

I tried to talk to her, but she went HISS! and swiped at me when I approached her. I sat with Mommy while she thought about any recent changes in the house and all she could think of was that she washed the big fluffy bathmat over the weekend.