I'm convinced there is a real productivity loss due to OSX's limited notifications system.

On OSX you get a tiny little bubble in the upper right from your chat program and if you miss it, too bad. I've seen people resorting to shouting or tapping on shoulders because of this. Trying to do something as simple as change the font size was difficult or impossible.

On linux I get nice big notifications. If I miss or choose to ignore them, my WM highlights windows that need my attention and they stay that way till I get to it.

There are fixes no doubt, but this lack of "customizability" permeates OSX and seems to be getting worse.