Originally Posted by Nightshade

Basic human psychology states that the things we do in one part of our lives eventually affects other if not all aspects of our lives.

Its the same idea as when looking at serial killers or murders. Generally it starts small with the injuring or killing of small things such as insects. Then it graduates to small animals...birds, cats, dogs, hamsters etc. Once the comfort in doing that and the thrill wears off they graduate to larger things and more impacting things to get the same feel and rush from it in order to sate their need and satisfy the urge.

Look it up in your psychology books sometime its considered a form of sociopathic behaviour.