What Just Happened?

I was sitting on the floor by my closet door talking to myself (I only do it occasionally. I'm not crazy, even though my family gives me crap about being crazy and talking really loud. They sometimes eavesdrop to hear what Im saying). I heard the bathroom door outside my closet open and close. Then silence. Because my family does eavesdrop, because I share a Jack and Jill bathroom with our office, and because my sister creeps into my room all the time to laugh at me because I talk to myself, I thought she was eavesdropping. Therefore, my thought process was that I was going to foil her plan by opening the door and catching her. Well it was really my grandma coming to ask me to make her food. And I had just smacked her in the face with the door.