You should be courteous to your coworkers.
Sarah is working with a new employee this week, named Bob, and she is trying to teach him the proper way to conduct a sales call.
Sarah wants to break Bob's habit of being too casual on sales calls.
Sarah conducts some role playing exercises with Bob to help him remember how to conduct a call.
Sarah tells Bob that she has already explained how to conduct a call and that if he is too incompetent for that simple task, that he won’t make it here.
Bob is appreciative of the lesson and it does help him to remember, while Sarah feels that she is doing well as a trainer.
Bob is offended by her remarks and gets upset, responding that he has a lot to remember during training, and she doesn't need to be rude, and Sarah feels badly.