I was working in the corporate headquarters for a large agriculture/construction equipment company.  The year was 1994, and many users were moving from the green-screen RS-6000 terminals to Windows for Workgroups with TCPIP (yeah.).   I was asked to install a new PC for the guy under the CIO, replacing his terminal.

I dropped the desktop to his office, then showed him how to log on, etc.

Me:  “Ok, move your mouse to the terminal emulation software and double-click.”

User picks up the mouse and holds it on top of the terminal icon and double-clicks the icon.  Against the monitor.

Me: “Umm…ok, the mouse works on the mouse pad…and I’m going to leave this icon here for you to practice with the mouse, it’s called ‘Meet the Mouse’.”

Exit, stage right.