This is a test which was circulating on the internet a few years ago. It's actually quite well done:
Read this question, come up with an answer, then scroll down to the bottom for the result. This is not a trick question. It is as it reads.
A woman, while at the funeral of her mother, met this guy whom she did not know. She thought this guy was amazing, so much her dream guy that she believed him to be just that. She fell in love with him right there, but never asked for his number and could not find him. A few months later she killed her sister. Question: what is her motive in killing her sister? (Give this some thought before you answer.)
Answer: She was hoping that the guy would appear at the funeral again. If you answered this correctly, you think like a sociopath. A famous American psychologist used this test to see if someone had the same mentality as a killer. Many arrested serial killers answered the question correctly.
If you didn't answer the question correctly, good for you.
The basic idea is that a normal (nonsociopathic) person could never even conceive of taking someone else's life so lightly that they would snuff it in order to gain what they want.
I know of exactly one person who got the answer correct, a woman who used to work on Wall Street. (I didn't ask her the question directly, but someone I had passed the question along to asked her, and told me the result.) This woman was a marvel of plastic surgery, including a pair of double D implants which she would flaunt at every opportunity. She would throw herself at men to get business from them. She always struck me as completely lacking in shame and embarrassment.