How many of them are there? Shouldn't there be a book or something? I guess they would be written then. Which ones make sense, and which ones are silly?
"Don't work the count when your team is up or down by a lot."
That's one you learn in little league. Maybe that's where all of these originate from?
"When hit by a pitch, don't rub the mark," or "when you slide into a base, don't dust yourself off."
Again, little league.
I found 2 of those here:
I hadn't heard of most of them on the list. But I guess there are a lot of these "unwritten rules."