nice man -l -Tdvi man*/* | wc 

3416771 6700199 122007116

At more than 6 million words, that's approximately 10 War and Peace's. And of course in terms of documentation, that's only man pages, which doesn't cover all the stuff that's in other formats like info or html.

You cannot be an expert in everything: I knew about that command for closing ssh, but frankly it is not something I use because it's easier to just close the rxvt and be done with it. I have zillions of other things to occupy my brain.

I'd also argue that in terms of ssh, since this function is so easily accomplished in other ways, this is really just handy triva. Much more useful to know about are all the tunneling things, as they are not necessarily obvious, and can be extremely useful.

"A little shame is a good thing" says to everybody around you that you're more interested in feeling good about yourself than helping people. And it's a joke to boot. I've been doing this for around fifteen years, I've written multiple telnet server applications and a MUD client, and I didn't know about this feature in telnet/rlogin/ssh.