We have a summer cabin in northern Wisconsin. (Actually my wife owns it jointly with her sister. It was built by their grandfather and passed down through the family. My wife and I take principal responsibility for maintaining it.)

The cabin isn't winterized, so every fall we have to drain the water out of the plumbing system so it won't freeze and burst the pipes. This involves opening and closing several valves. My wife is younger, smaller, and more agile than I am, and she is better at squeezing into small spaces than I am, so she usually does the work while I supervise.

She has memorized the phrase "righty tighty, lefty loosey" and is able to apply it correctly as long as she is looking at the valve straight on, but if the valve stem is pointing away from her, and she has to reach around behind something to put her hand on it, she always gets confused. Fortunately, she knows she gets confused so she always asks me which way to turn it. At times like this, she also gets confused about left and right, so she asks me: "Do I turn it toward the lake, or turn it toward the highway?"

By the way, the trend these days is for plumbers to install ball valves rather than the older gate valves. My wife finds these less confusing because the handle only moves 90 degrees, and it is easier for her to remember that the valve is open when the handle is parallel to the pipe, and closed when the handle is perpendicular to the pipe. I like them too, because you can tell at a glance whether the valve is open or closed, and you can't over-tighten them.