When Outlook gets disconnected from the mail server (for whatever reason) there is no pop-up or warning to tell you that you're not seeing your new e-mails as they come in anymore. It just writes "not connected" in small writing in the bottom right corner of the Outlook app (for Mac). I'm pretty sure it's the same on Windows.
I've lost track of how many times I've wondered why I haven't received an e-mail I should have by now only to eventually look and see that it's no longer connected. Surely this should be displayed more prominently and a popup should notify you, instead of silently staying disconnected.
I agree. So far as I am aware there is no option to make the disconnection state a notification or more prominent - I note that sometimes my Outlook icon on the taskbar will show a exclamation mark but that can be easy to miss too.
There is a uservoice relating to this - the more votes the better the chances MS will implement this.