Hurt

I don't understand why people feel better by hurting others.
My boyfriend posted on Facebook a story about how he threw a street preachers pamphlet in the gutter, and how the sadness that caused the man gave him enough joy to navigate the day.
A friend told me she didn't understand how her daughter has been so joyful when she had a birthday party and had isolated and ignored one of the girls invited. Yet she had done the same thing to me just a week prior to gain favor with another aquaintance.
This leaves me to wonder if I myself do this sort of thing to others. I hope not.