Am I misunderstanding windows 10 notifications

[cgk]

So you set up the app notifications you want and then.. well I'm not sure... notifications seem complete random - some times you get notifications for an app and then at other times no notification. Many of the notifications appear only *after* you have opened an app so they aren't notifications they are a note about the past.

I find this occurs across all of my machines (I have four w10 devices).

Am I missing something or is it just a broken system?