There is a neat little word, coined by Albert Ellis, for the tendency to incorporate shoulds into your life. It is "musterbation". You are "musterbating" whenever you find yourself behaving in ways that you feel you must, even though you might prefer some other form of behavior. Karen Horney, the briliant psychiatrist, has devoted an entire chapter of Neurosis and Human Growth to this topic, and she titles it, "The Tyranny of the Should." She comments:

The shoulds always produce a feeling of strain, which is all the greater the more a person tries to actualize his shoulds in his behavior.... Furthermore, because of externalizations, the shoulds always contribute to disturbance in human relations in one way or another.

Do shoulds determine much of your life? Do you feel you should be kind to your colleagues, supportive of your spouse, helpful to your children, and always work hard? And if at any time you fail in one of these shoulds do you berate yourself and hence take on that strain and disturbance to which Karen Horney alludes above? But perhaps they are not your shoulds. If, in fact, they belong to others and you have merely borrowed them, you are musterbating.