Well fine I guess but when I write "liken to" it has a meaning, I'm trying to illustrate one thing in terms of something else rather than make a working explanation of the first. I'm trying a step back, not a step into.
When I wrote "Much code may be spent on ways around that. ", it's not a recommendation to do that. It's more like a recipe for spaghetti.
But any of this that can get any beginner able to see what blocking is and learn to avoid it.
Blocking is
finger(code execution)
stuck(blocked)
on the button(delay(),readUntil(),etc).