“The speech of the neurotic is notable for such expressions as ‘I ought to,’ ‘I should,’ and ‘I shouldn’t,’ indicating the individual’s self-image as an inferior man or woman, always falling short of the mark, always making the wrong choices. The speech of a person with a character is disorder, however, relies heavily on ‘I can’t,’ ‘I couldn’t,’ ‘I have to,’ and ‘I had to,’ demonstrating a self-image of a being who has no power of choice, whose behavior is completely directed by external forces totally beyond his or her control.”

in M. Scott Peck, Psychology, Writers