This might be something to do with effect of not winning every time: it's studied method to get and keep us addicted. You will get a bigger dopamine hit when on

This might be something to do with effect of not winning every time: it's studied method to get and keep us addicted. You will get a bigger dopamine hit when only some of notifications are "wins" like tagged photo etc. Slot machines are a great example of this along with other gambling.