For many years I've heard that when youngsters get angry that they can produce psychokenetic-type effects, like moving and manipulating objects, etc. There have been Movies and many Television Shows based on this phenomenon,,,the most extreme and most well known of The Motion Pictures made on this subject has to be "Firestarter," but even the movie "Matilda" was loosely based on this paranormal ability in kids.
In your case though, I'd almost be willing to bet that someone left an oily hand print on your shower wall and that when the water hit it, it became visible to you. I'm also pretty certain that when you were playing your game and got angry that you physically shook the chair and didn't realize it. I think that you just imagined that it moved on it's own accord or by unseen forces.
However, if you start making things fly off of shelves or dance around the room with your mind, then THAT would be very interesting!
