I dont know why they do it, But I was stalked at one time in my life and it was a pretty scary thing, This person was completely obsessed with me and I have PTSD still from it, He even tried kidnapping me, He was Psyco to say the least, He watched me everywhere, I had no privacy, There are laws in the United states where stalking is a felony and people go to prison and they should people are murdered by stalkers every day