This research was aimed to investigate how public service patients, having a positive experience of their psychotherapy, evaluated different therapeutic factors. Twenty-three patients have been interviewed and administered the Therapeutic Factors Q-Set (TFQS): a list of 50 therapeutic factors to order from the most useful to the less useful, according to Q methodology. The following factors prevailed in the Therapeutic Factors Q-Set (TFQS): the sense of security conveyed by psychotherapist’s help and support, psychotherapist’s professional capability, and developing more self-esteem and regard for myself. Q factor analysis led to six subgroups of patients with respect to the value given to the different factors. Q methodology allows to catch the psychotherapy’s idiosyncratic features.