Technology is acquiring the capability to sense and respond intelligently to human emotion. What is driving this progress? I will give examples of the potential for good with this technology in autism, epilepsy, and helping with mental health such as anxiety and depressive disorders. However, the possibilities are much larger: Affect sensing is being used to make ads and educational videos less boring and more fun. Social robots will need emotional intelligence (including the ability to read our emotions in our homes) in order to not annoy us. Some organizations want to sense human emotion without people knowing or consenting, for example, to detect possible terrorists in public settings. What can we do to help make sure that new affective technologies make human lives better?