I wouldn't trust Amazon or any other tech giant with data about my emotions, that information is more personal to me than the contents of my day to day conversations or any other biometrics they might be scraping. What an unimaginable panopticon we are entering into.

But in a dream world, I would love a device that could help me map out my emotional state over time. My emotional health is a huge component to my well being. I currently manually keep an offline journal of my mood daily and use it to better understand myself, offloading that to a passive monitor would be great.