Believe it or not but the way our minds are designed we react to visual and audio stimulation through our senses realm and when something is dramatic or filled with intensity then it peeks the mind's sensory response and then increases our heart rate and that sends a signal to that area of our brain that is somehow stimulated similar to what nicotine and alcohol does just not to that high level. It's not the violence that stimulates but the tension and excitment rush that activates our always hungry senses.