The doctoral thesis entitled "The influence of consumer characteristics and situational factors on the shape of the relationship between satisfaction and returns on satisfaction" provides a comprehensive overview of relevant theories and empirical research related to the subject of the thesis. One of the main goals of this doctoral thesis was to determine whether the shape of the relationship between satisfaction and returns on satisfaction will change, and in what way, under the influence of different consumer characteristics and situational factors. In the empirical part of the thesis, four on-line experiments with hypothetical scenarios were conducted within three different services. Testing was performed in relation to two dependent variables that were possible outcomes of satisfaction (loyalty expressed in the form of intentional behavior and willingness of the user to pay the service). GAMM model was used to test the hypothesis. The results of the analysis showed significant influence of consumer characteristics (involvment, experience) and situational factors (length of the relationship, functional/hedonic motives (context)) on the shape of relationship between satisfaction and returns on satisfaction, but also on the level of service tolerance. There are evidence of linear, "S" shape and an inverse "S" shape of the relationship. The results also indicate that the relationship may change significantly depending which dependent variable is used. The relationship between satisfaction and different returns on satisfaction is not always linear, so focusing on consumer satisfaction alone, as it was usually the case with the theory and practice so far, is not enough. Companies can apply a similar procedure suggested in this paper in order to better predict consumer behaviour. In this way, it would be possible to determine for which consumer segment would be more effective to increase the level of satisfaction (to delight them) and for which consumer segment would be more effective to reduce the level of dissatisfaction or to maintain the existing level of satisfaction.