On top of that if we did not ground one side of the electrical network, you could touch either wire and feel nothing. That's called an isolated ground, and is not commonly used except in hospitals and some other specialty settings.
(If you wonder, we ground one side because if two different people both happened to touch a wire, current would flow between them using the each.)
But at the scale of a national grid it's basically impossible to ensure that the entire grid is isolated from the ground all the time. Stuff breaks. And if the network is grounded in some far away place but not anywhere near you you get exactly the effect you describe: you have some unknown and potentially large voltage differential towards ground because the literal ground doesn't have the same potential everywhere. So instead you give up and tie one of the potentials to ground, and do that as often as viable.
However if you set things up so that one terminal of a 9v battery is grounded, and you lick the other terminal (just one), you would feel something.
(You would also have to be grounded, at 9v that would probably require barefoot on slightly wet ground. At 120v it's a lot easier to be grounded, but the principle is the same - you only feel the electricity because the ground itself provides a return path.)
What I could never keep straight is anode and cathode.
"CCD" -> "cathode: current departs"
In chemistry though, cations are positive ions and anions are negative ions.
It makes perfect sense! Cations, you see, are attracted to anions. And reduced by cathodes. Anions? Attracted to cations. And oxidized by anodes.
Whereas cations are oxidized by anions, and anions are reduced by cations.
The only alternative here would be if cathodes and cations were positively charged, and anodes and anions were negatively charged. But then cathodes would reduce anions, and cations would also reduce anions. Even worse, anodes would oxidize cations, and anions would also oxidize cations.
And we can't have that. It would just be too confusing.
I just let my eyes skip over that list. I refuse to be the Jaguar in "Just-So Stories" https://etc.usf.edu/lit2go/79/just-so-stories/1294/the-begin...
I believe https://chemistry.stackexchange.com/questions/16785/positive... is correct.
The terms anode and cathode should be burned. We don't use them much in modern electronics. E.g. we don't say that the positive power pins of a CPU are anodes, or that ground pins are cathodes.