Personality is the unique self-expression of the individual. There are innumerable more sophisticated and complex definitions of personality, but this provides a good starting point. This self-expression may be internal or external, private or public. A companion assumption is that each person chooses his or her self-expression, and no person will be anyone that s/he isn't or cannot be. Everyone will always be who they really are capable of being at any given moment in time. These assumptions remind that all persons are involved in adjusting to whatever their versions of reality or experience happen to be, and they truly are doing their momentary best!

It is impossible for any individual to express him or herself completely (and it would be very boring, even if it were possible). Therefore, to know another person completely is also an impossibility. The crucial question then becomes, "What am I going to do with that measure of incomplete self-expression confronting me in this particular person and situation? or, "What will I do to respond adequately now, today, to promote further, more complete self-expression and growth in myself and other individuals?"

Responsibility can mean cultivating the capacity and repertoire to respond as adequately as one can, and does not automatically mean meeting another's expectations or behaving in a "socially correct" manner. In fact, it may frequently mean behaving in unexpected or novel ways, especially if high value is placed upon challenging stereotypes and encouraging others to think about their assumptions and how they relate. Harry Stack Sullivan referred to this as "upending expectancies" which others may hold, in order to encourage personal growth. In THE PSYCHIATRIC INTERVIEW he also suggested relating to other persons with an attitude of "undecorated respect".