What makes someone stalk you, or what qualifies as a stalker?

A stalker is someone who is obsessively following someone on the verge of infringing on her rights.

What makes them like that though?

obsessio

What makes them like that lies in the fields of psychology. Some says it's love, or adoration, or worship, which ever you prefer. Or perhaps something even more sick. Sometimes it's just selfishness, the want to keep you close to them. That's the usual things encountered.
It's too bad for you if you get the sadistic kind that just loves messing up your life. This one stalks people because they feel superior when they hurt someone. Imagine the power they feel when they hold a life in their hands. It's sick, but they love the rush of it.

@meow, wow. that's deep.