Clearly he just wanted to make sure that it actually was connected properly... but I like to think he was making sure the Internet was flowing into my computer. With those unidirectional Ethernet cables you have to check.
"Please reboot your computer" serves a similar purpose. Rebooting hasn't actually fixed any network connectivity troubles since approximately Windows 95, but the action serves as proof that 1) the customer actually has a computer, 2) they are at it, and 3) it's turned on. They really will have those basic facts wrong and lie about them if directly asked. ("Their computer" could be at their nephew's house, or be a TV.)
He could type for a while after I was back to my desk and before the keyboard went dead and he started to curse about a quarter of an hour of work lost. Everybody was laughing out loud, and louder because he was seeing that I had something to do with it but he can't figure out what.