Editing Cognitive distortion (section)

=== Should/shouldn't and must/mustn't statements ===
Making "must" or "should" statements was included by [[Albert Ellis (psychologist)|Albert Ellis]] in his [[rational emotive behavior therapy]] (REBT), an early form of CBT; he termed it "musturbation". Michael C. Graham called it "expecting the world to be different than it is".<ref>{{cite book|last1=Graham|first1=Michael C.|title=Facts of Life: ten issues of contentment|date=2014|publisher=Outskirts Press|isbn=978-1-4787-2259-5|pages=37}}</ref> It can be seen as demanding particular achievements or behaviors regardless of the realistic circumstances of the situation. 
* Example: After a performance, a concert pianist believes they should not have made so many mistakes.<ref name="about" />
* In ''Feeling Good: The New Mood Therapy'', David Burns clearly distinguished between pathological "should statements", [[moral imperative]]s, and [[social norm]]s.
A related cognitive distortion, also present in Ellis' REBT, is a tendency to "awfulize"; to say a future scenario will be awful, rather than to realistically appraise the various negative and positive characteristics of that scenario.
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.<ref name="burns" />