You know those handheld tally counters, where you click and a counter goes up?
This is that.
For example, your doctor wants you to note how many glasses of water you have per day. Create a counter called "water", and every time you have a drink, tap the +1. The app will timestamp each tap, and tell you how many glasses of water you had in the past hour, the past day, the past month. Tap a number to see a graph over time.
You don't even need to open the app. Just edit your counter to "pin" it. That creates a shortcut on your home page. Just tap the shortcut to increment the counter.
That's all it is. It's my first app. It probably has bugs.