Life's questions

So today I had to train on a new spot I was given at work. Well this one girl is a little mad that she didn't get it. So now she is doing everything she can to make it hard for me to train. She is even trying to get me in trouble! I really don't understand people sometimes! Why do something to hurt someone because they got something you didn't? I'm not like that I'm happy for people when good things happen to them! I don't know it just hurt to have her do that to me today!