The app is open in the background constantly, and you already have predefined the activities so you just press on it and that's it, it literally takes a second.

The app is open in the background constantly, and you already have predefined the activities so you just press on it and that's it, it literally takes a second. As for the sanity of it, it just becomes a habit like any other, e.g. you check for your keys when leaving your house, you just also check on the app the correct activity.