And from what I’ve been able to find online, it appears that the words “right” and “left” to refer to directions started as referents to hands, and only then became more general. Your “left” hand is the one that’s relatively weak and worthless (if you’re right-handed, like the majority of people); and then “(on) your left” = on the same side of your body as your left hand.
At U.S. 4-way stop signs, in general the first vehicle to arrive has right of way. But for simultaneous arrivals from orthogonal directions, the driver on the right has the right of way. I knew someone who was totally convinced that this was the only possible way the universe could be arranged, because they “had a right”; rather than being an essentially arbitrary convention that’s just easier to remember - the person on the right has the right of way.
I do wonder if this strange perception is more widespread, and contributes to the difficulty so many American drivers seem to have with roundabouts, where in the U.S. the driver on the left (i.e. already on the roundabout) has right of way.
Reminds me of an old joke:
Are you all right?
No, half of me is left!
It’s okay to not like a usage that dates back for centuries, but it’s factually incorrect to imply that just because you don’t like it, it’s a new and childish thing.
Here’s a link to a listing of a few hundred books that use “right hand side” - textbooks, dictionaries, law books, etc., from about 200 years ago.
So, i think that’s a subtle difference between “left” and “left hand”. I think the former can be ambiguous, but the latter always means the left as compared to the person being referred to, just like “port” is the left of the ship and “stage left” is the left from the perspective of the actors looking at the audience.
That is:
But i do also think that the value of redundancy and the possible confusion with “correct” helps to make this a common usage.
Do you live somewhere with alternate side parking? I do and saying something like “make sure you park on the right side of the street” is unambiguous and always means “the correct side” , although that may be because unless you are parking on a one way street, parking on the left side might get you a ticket.
I myself see what you did do there.
I’ve never consciously thought of “left-hand side” or “right-hand side” as referring to actual hands. To me, they are just words that describe things on the left or right. I hear them all the time and they sound completely normal.
No, don’t have that here. I’d say “correct side of the street” in that usage, but if “right side of the street” is unambiguous where you’re at, that works, too.
ETA: Now that I think of it, we do have street cleaning every so often, and I park on the right-hand side of the street normally, but if somebody said to me “hey, don’t forget to move your car to the right side of the street” on a street cleaning day, that would actually sound perfectly normal to me, meaning to move it to the correct/left side.
We have street sweeping here, too; on our street, parking is prohibited on our side of the street on Mondays, and on the other side on Tuesdays.
After we inherited my late father-in-law’s Corvette a couple of years ago, we wound up with three cars, one more than the capacity of our two-car garage. So, our Mazda SUV is parked on the street; usually, it’s parked directly in front of our house, but we need to move it on Mondays during street-sweeping season.
If one were driving down our street (it’s a one-way street), our house (and where the Mazda usually gets parked) would be on the left. But, when my wife and I are reminding each other to move the car, it’s “the other side” versus “our side.”
Clear as mud. 
Yeah, I think “the other side” would be the usual construction for me or for my wife, as well. But if she were to use “right” it would be understood and unnoticed. That said, she could just say “make sure to move the car” and that would be clear enough.
We also say “on hand” to mean having something immediately available, as in “We have ten bottles of WD-40 on-hand” meaning “We have ten bottles of WD-40 in stock”.
Hebrew has a somewhat similar idiom: “al yad”, literally “on hand”, means “nearby”, as in: “The chair [is] on hand the table”, meaning “The chair is near the table”.
I think difficulty with immediately being able to tell right from left with no props occurs in those who do not have a strong dominant hand. Both my youngest sister and my wife were probably natural lefties who were trained to be right handed (as was done in those days). Both of them have right left difficulties.
My wife when looking at maps used to often tell me to turn the wrong way. She no longer says left or right, but wedding ring side for left.
This is clearly is not an intelligence thing as she’s an MIT graduate.
Sadly, for me I’m extremely right hand dominant and I still struggle with L and R. The “make your hand do an L” trick never worked for me.
I have dyscalculia and struggled with right and left all my life. It has to do with abstract spatial and numeric relationships. It’s a physical part of everyone’s brains where that stuff lives, and if you have dyscalculia, that’s a dimly-lit room. Does not have to do with dominant handedness particularly. Nor does it have anything to do with intelligence per se.
This prompted me to wonder if there is a dys- word for left-right confusion. It seems not, although (as you are probably aware) there is a rare condition called Gerstmann Syndrome.
Gerstmann syndrome - Wikipedia
Gerstmann syndrome is characterized by four primary symptoms, collectively referred to as a tetrad:
- Dysgraphia/agraphia: deficiency in the ability to write[3][4]
- Dyscalculia/acalculia: difficulty in learning or comprehending mathematics[3][4]
- Finger agnosia: inability to distinguish the fingers on the hand[3][4]
- Left-right disorientation
Japanese often uses “right hand” instead of right side. Such as まっすぐ行って右手にあります (Go straight and it’s on your right hand (side).)
There was a song put out by a comedian 山田邦子 Kuniko Yamada years ago, in which she plays a tour guide and says: 右手をご覧ください。 一番高いのが中指でございま～～す。 わ～～ははははっ。Please look on the right. (Literally, please look at the right hand. The longest one is your middle finger.) That dad joke is only possible because Japanese uses “right hand” to mean “right”. The Japanese word for “correct” is completely different so it’s not a matter of trying to differentiate between right and correct.
Something interesting about kids is that kindergarten children will generally mirror your actions. When teaching a dance move, for example, you need to hold out your left hand if you want them to hold out their right hand. Older kids will do opposite actions so if you hold out your right hand, they will as well.
From my experience, this changes somewhere around first to second grade.
Abbott: Why sure I’ll introduce you to the boys. They give 'em funny names though
Costello: Oh I know they give those ball players awful funny names
Abbott: So the player on first is named ‘Who’. After him, a player whose name is ‘What’, and third, another player with a most unusual name, which is ‘I Don’t Know’
Costello: I understand perfectly.
The only requirement for a memory aid is that it works for the individual using it. She has no issue remembering which way around her hand goes.
The most useless memory aid for me is the poem for remembering how many days there are in each month. I can’t remember the poem because it seems, to me, to be an arbitrary list of months and numbers of days. “30 days hath [list of months], all the rest have 31 except for February etc etc.”
Agreed. For me, that poem is just as hard to remember correctly as the information it attempts to codify; it’s not as though it necessarily fails to scan/rhyme if you get it wrong.