Hound Dog wrote:
I went to good toilet and tried the exact same motions--turning the valve
all the way to my right. Then I flushed it, flushed it again, and the
tank emptied almost all the way. Period. It didn't start refilling until
I started turning the valve to the left. So WHY is bad toilet refilling?
There's nothing else I can do--I've turned the valve as far to the right
as I can.

Your shut off valve may be stuck.
Spray your shut off valve stem with WD40 and let it set for an hour or so.

You should check your valves several times a year to make certain the
handles turns easily and turns all the way on and off.

I've actually done that. After the old toilet (that this one replaced)
overflowed and flooded my house because the valve was IMPOSSIBLE to
turn, I had it replaced. So the valves on both toilets are new (3 years
old) and they turn freely and easily, which I check periodically.

But...since turning this one all the way to the right is NOT shutting
off the water, I guess there *is* a problem with it. I just don't know
what. And my friend/contractor who installed them is gone so I can't
ask him to look at it. :-(