Body monitoring devices are increasingly turning into machines that not only track personal activity but also provide suggestions on how to lead a life that is assumed to be continuously improved. By measuring, interpreting and correlating various data sources, these devices are assumed to provide an understanding that goes beyond everyday self knowledge. Although these devices most certainly can provide information on how to run faster or sleep better, it remains unclear how it feels to gain a deeper understanding of oneself by means of a technological device. This paper approaches this question in an auto-ethnographic study (by the author of this paper) where the Jawbone UP wristband and the ”Smart Coach” insight and coaching ”engine” will be used and the suggestions for improvement slavishly followed during 100 days. This system crunches personal data in various ways in order to provide ”actionable insights and uniquely personalized guidance” (jawbone.com).