Confusion lies in the rules that “possessives use an apostrophe” but “possessive personal pronouns don’t use apostrophes”. Regardless of how those rules came to be, it’s maddening how much confusion they cause.
So possessives are contractions! I did not know this - thank you!
Yes, i find “its” somewhat annoying.
It’s especially annoying when people misplace it’s’s apostrophe or its’s apostrophe and pretty soon it’s impossible to tell which its is its and which is it’s. Isn’t it?
You’re welcome. 
That outlier is probably also contrived, not something you’d likely see in the wild.
There’s a very sound principle behind the Oxford comma. In a phrase like “A, B and C” it can be ambiguous whether it means the pair “A” + “B and C” or the triplet “A”+“B”+“C”. When written as “A, B, and C” the ambiguity vanishes.
ETA: I just realized I misread what was being said, but I’ll go ahead and post this anyway…
I see examples in real life occasionally. I edit science newsletters where the writers are trying to cram a lot of information in as tightly as they can.
There was a famous court case that hinged on a missing serial comma. It happens.
There’s nothing wrong with that, but I think it’s unnecessary and maybe even a little pedantic. When the apostrophe appears in contractions, it’s part of the prescribed syntax of those words. It helps identify them for what they are, and avoids possible confusion with other similar words – “can’t”, “cant”, “won’t”, “wont” are all valid words. There is no such convention for abbreviated years.
But something like “50’s” drives me nuts. It’s the “grocer’s apostrophe” in all its glory: “Apple’s and orange’s on sale today!”.
Many style guides disfavor the Oxford comma. Interestingly, despite its name, it is used much less frequently in British English than in American English. I usually don’t use it unless it’s clearly needed to remove ambiguity. I think there are just as many cases where it introduces ambiguity as those where it removes it.
A not very contrived example: “The people I most admire are my brother, Tom Hanks, and Albert Einstein.” Here the Oxford comma makes the sentence ambiguous, as “Tom Hanks” can be read as an appositive for “my brother”; that is, that I admire two people and that my brother is Tom Hanks. Without the Oxford comma it is clear that I admire three people.
Of course that’s the calculation I made when I decided to use the serial comma in my own writing. The reason to use it is pretty obvious. The argument against it is odd.
I find autocorrect particularly boneheaded about its and It’s - very often it corrects its to it’s when it’s its, and it’s to its when it’s it’s.
I don’t find that very persuasive, especially not compared to the systematic ambiguity inherent in omitting the Oxford comma.
There are numerous examples where the English language is just inherently ambiguous and the only solution is to rephrase the sentence. But if we’re going to argue solely about punctuation, I’ll just point out that the pairing of the last two items in a list, in this case “Tom Hanks and Albert Einstein” is precisely the problem with omitting the Oxford comma, because most of the time it’s not meant that way. It just happens that in this special case it is.
My other observation is that if “Tom Hanks” were really the intended referent for “brother”, why have a comma there at all? After all, there’s no comma in “My brother Tom and I went fishing”.
An example of the opposite (which I think is more common)
"The people I most admire are my parents, Albert Einstein and Mother Teresa.” which reads as if I admire two people and Albert Einstein and Mother Teresa are my parents. It’s not ambiguous at all - it just means something very different than it would with the Oxford comma.
Absolutely everyone rags on that movie for so many valid reasons, not neglecting the terrible accents, but if you actually sit down once and watch it uninterrupted, it manages to work.
No; it is plural, so you would write the 1950s’ wild parties, or the Fifties’ parties, or perhaps the parties of the eighteen-fifties.
In that case my feedback on this would be yes, “50s’ wild parties” (the plural form) would be syntactically correct, but stylistically awkward. “The 50s” did not throw wild parties; young people did. “The wild parties of the 50s” is much better.
ETA: Edited as @DPRK is correct – “50s” must be a plural.
Hey, welcome back! I noticed you weren’t posting for a long time.
Thank you for your kind words. I’m happy this place is as active as ever. 
By coincidence, I just ran into an example of the ambiguity of the Oxford comma in the wild, although perhaps I wouldn’t have noticed it without having read this thread recently. I’m reading The Merry Wives of Windsor in preparation of seeing the play next week. In Act III scene I, Simple says “There comes my master, Master Shallow, and another gentleman.”
How many people are coming, two or three? Only having by the knowledge that Simple’s master is Slender, not Shallow, can you tell that there are three people approaching.
Out of curiosity, I grabbed a high school English book which has faithfully followed my wife from residence to residence since the 1960s. It says, quite prescriptively
Use the apostrophe and s to form the plural of letters, numbers, and signs, and of words referred to as words.
As a specific example it includes “That happened back in the 1930’s.”
Then I dug out her 1976 edition of Webster’s Secretarial Handbook and it also prescribes using the apostrophe.
Also see pulykamel’s 100+ year old cite from the Chicago Manual of Style.
What that means is that for at least some of us, we had it figuratively beaten into us that THE CORRECT WAY to refer to the 1930s is to use “the 1930’s.”
Granted, a lot has changed since 1976, but if you’re not a professional writer, you probably haven’t kept up with the nuances in style. And this seems an insignificant issue to correct a poster on, even on a Board as nit-picky as this one.
Rather than the apostrophe in decades, I’d rather the mods ban yet another argument over the Oxford Comma!
Right. All of these people saying it’s “wrong” to use an apostrophe are confusing correctness with following a style.