According to Burns, “must" and “should” statements are negative because they cause the person to feel guilty and upset at themselves. Some people also direct this distortion at other people, which can cause feelings of anger and frustration when that other person does not do what they should have done. He also mentions how this type of thinking can lead to rebellious thoughts. In other words, trying to whip oneself into doing something with “shoulds” may cause one to desire just the opposite.