Patient experiences surveys have become common within healthcare and represent an important form of participation, with patients having the potential ability to influence the quality of care. However, there is still a relatively limited understanding of how patients evaluate the quality of their care. We present the findings of a qualitative study, which explored the way in which patients express their evaluations, in an attempt to move the debate forward. The results indicate that patient evaluation appears to be far more complex than routinely acknowledged, particularly in relation to the expression of negative experiences. Patients were reluctant to offer directly negative criticisms, needed particular conditions in which to express their negative evaluations and used a variety of adaptive strategies to overcome social pressures that inhibited negative evaluation and promoted positive evaluation. We argue that standardised approaches to measuring negative evaluations, such as questionnaires, need to become more sensitive to the complexities of negative evaluation. This would enhance the extent to which patients can participate in influencing the quality of care. A number of recommendations are made to develop the sensitivity of future investigations into the negative aspects of patient experiences.