1AppMode is a productivity utility that resides in your macOS status bar menu. Turn it on to focus on one app at a time.
Its perfect for presentations and times when you really need to focus.
It also makes getting to your desktop or the Finder much easier: just click the desktop and the Finder/desktop becomes active.
If things ever get whacky or you need to use two apps at the same time, deactivating the service is as simple as clicking "Turn Off" in the 1AppMode menubar.