In the 1979 book “The Meaning of Things” Csikszentmihalyi and Rochberg-Halton studied people's perception of the significance of things in the home. They emphasized how things influence the self, and vice versa. We propose that their method and analytical framework can help to understand the analogous question for smartphones: Why are some apps special to users? Using the framework, we conduct and analyze 60 interviews with people aged 21 to 41; with participants' consent, we made the anonymized transcripts publicly available. The analysis of the interviews shows that participants find apps special because they are convenient, support personal goals and social communication, help them remember, and serve emotional functions. Participants report that their identity is intertwined with certain apps, even if they are annoying or cause dependency. Importantly, we also find that participants actively regulate their use of apps through their organization and particular use strategies.