I love a command line. It's numerous advantages over GUI is hard to list, but there are situations, where you need a remote X Windows connection. I've been asked many times by my colleagues, how to set up remote X Windows (X11, as the most recent version of X Windows is 11) on AIX, why it doesn't work, etc.
Basic overview of X11 Windows architecture
X11 is a client / server architecture. You need to know two things:
an application e.g. xclock is an X11 client
the application's content is displayed by an X11 server