Google's Glass has captured the world's imagination, with new articles speculating on it almost every day. Yet, why would consumers want a wearable computer in their everyday lives? For the past 20 years, my teams have been creating living laboratories to discover the most compelling reasons. In the process, we have investigated how to create interfaces for technology which are designed to be "there when you need it, gone when you don't." This talk will attempt to articulate the most valuable lessons we have learned, including some design principles for creating "microinteractions" to fit a user's lifestyle.