A Fatal Attraction

I become very angry when somebody realizes the obsession my kitten has with a laser pointer, and then proceeds to tease her with it.  I think this supports a common obsession humans have with causing animals to do pointless things.  Why do we taunt cats with dangly things?  Why do we cause dogs to fetch, roll over, and sit up?  I guess animals just have too small of a brain to realize the stupidity of such pointless behavior.