This paper presents part of the research result from the project eCAALYX – Enhanced Complete Ambient Assisted Living Experiment in which the authors were responsible for the design and evaluation of a TV-based user interface for older adults with chronic conditions. The curiosity to understand the impact of performing usability testing had in older adults led the authors to evaluate the feelings of happiness and fatigue before and after usability testing. This evaluation was conducted five times in a set of eight usability tests performed over thirteen weeks. Results show that these two feelings improved in the usability tests. In this paper, the authors develop an understanding of what may justify this improved self-sense of happiness and fatigue; following principles that favor older adults wellness during usability testing may be the main reason for these results.