You may recall the Tamaguchi craze from the late 90s, i.e., the "little digital creatures" that needed constant attention. That version was kinda annoying.
Here's an idea for Tamaguchi 2.0, an app that tracks your mobile phone habits (without collecting detailed data on words or actual apps) and then creates a "fingerprint" based on, e.g., "wake up and use phone for 10 minutes..." or "call only on weekends" etc. The idea is that everyone uses their phone in a specific way.
The app *then* hangs around and only pops up when you're using your phone in a different way, at which time it pops up and asks "how's everything? you ok?" and allows you to say "all good" or "I'm depressed" or "I'm traveling" or "I have a new partner" etc. Then the app gives a little feedback (e.g., thumbs up for travel but "maybe call a friend" for depressed)
It need not be invasive, and the data will only reside on the device, as it's unique to you.
Any app developer types out there are free to use this idea... I only ask for a thanks (and update!) if you go ahead with it :)