Read this story & question, come up with an answer. If you get it right, you are a psychopath, if you get it wrong you are a cycle path. I'll post the answer when I can be bothered.

A woman, while at the funeral of her own mother, met a guy whom she did not know. She thought this guy was amazing. She believed him to be her dream guy so much, that she fell in love with him right
there, but never asked for his number and could not find him. A few days later she killed
her sister.

Question: What is her motive for killing her sister?