Culture is about how, not just what, people think. Recent social theorists suggest that personal culture is best observed not in 'the self' as an entity, comprised of a set of attitudes, but in the self as a practice, a style of developing and holding attitudes. Very rarely, though, do we observe the practice of self unobtrusively, and at a scale we can formally analyze. We don't know what kinds of thought processes, emotions, and moral logics actually arise in self practice. I access transcripts of 1,705 psychotherapy sessions, covering 42 clients, that occurred between 2010 and 2014 in Massachusetts. Therapy aims to provide a 'backstage' where the self can be practiced. Computational text analysis finds that the practice of self involves secondary, rational thought processes concerned with time and instrumental behavior more than it does primary, intuitive processes. It involves individualizing moral logics more than binding ones. This pattern of self practice is similar regardless of the substantive topic and client gender, with the exception of the topic of sex. There is a structure to the practice of self. I discuss the implications of this for theories of culture.