The Facebook “Messenger” app pops up a full-screen modal pestering you to enable notifications EVERY TIME you start it, if you choose to keep them disabled. I prefer to batch electronic communications and check them a few times a day at most, and find the constant nagging to change my communications style pretty infuriating. I ended up deleting the app.
ok, but given that Messenger is about, err.... real time messaging it is probably very important to have push notifications enabled.