The scenario above describes user experience of communicating with a relative via text messaging with a mobile phone. We can investigate user experience on many temporal levels, however. In the scenario above, we could study Lisa's changing emotions during interaction, her feelings about the episode as a whole, or her attitude towards her phone in general, i.e., her overall UX. In the above example, focusing on the momentary emotions may not be the best way to understand Lisa's user experience, since her emotions were caused mainly by the content (the messages from Lisa's husband) and not by the examined system (mobile phone). However, in systems where the content has the primary focus, such as in electronic games, the flow of emotions may be the best way to evaluate user experience.
Single experiences influence the overall UX:: the experience of a key click affects the experience of typing a text message, the experience of typing a message affects the experience of text messaging, and the experience of text messaging affects the overall UX with the phone. The overall UX is not simply a sum of smaller interaction experiences, because some experiences are more salient than some others. Overall UX is also influenced by factors outside the actual interaction episode: brand, pricing, friends' opinions, reports in media, etc.
One branch in user experience research focuses on emotions, that is, momentary experiences during interaction: designing affective interaction and evaluating emotions. Another branch is interested in understanding the long-term relation between user experience and product appreciation. Especially industry sees good overall UX with a company's products as critical for securing brand loyalty and enhancing the growth of customer base. All temporal levels of user experience (momentary, episodic, and long-term) are important, but the methods todesign and evaluate these levels can be very different.