One of the many tools in the toolbelt of Cognitive Behavioral Therapy is to train your brain by reinforcing good things. A mechanism to do this is to write down 3 things that you appreciate each day. However, I believe the effectiveness of this tends to dim, as you have a couple of things which you lean on by default and the magic wears off.
So the idea here is that this would be a bot that asks you for the things you appreciate, and can really poke and prod and get you to think instead of taking the easy answers. Of course by doing so it is aiding you by helping you find the things that you appreciate. How? I dunno, magic.
I believe Good Times 4 Bad Times is a better idea. http://athoughtadrift.com/ideasbook/2018/09/11/good-times-4-bad-times-phone-photo-app/