So QPT (Question Person of Today), yes, there are certainly instances in which rules collide, harmony departs, chaos appears imminent. Well, thats exaggerated.
Heres one I ran into while reading1920: The Year of the Six Presidents by David Pietrusza. I failed to mark it properly on my Kindle, so Im substituting a town name. The author made a possessive of the name including its state and placed it in the middle of a sentence. Using Canton, Ohio, in the middle of a sentence requires a comma between Canton and Ohio and another comma after Ohio, an oft disregarded rule, but still a rule. Making a possessive of Canton, Ohio, gives us Canton, Ohios. Putting that in the middle of a sentence produces Canton, Ohios, whatever, and this is awkward. The author or editor chose to omit the comma after Ohios.
A simple fix in a collision of rather straightforward rules.
Now going into deeper water, well find challenging material in an online discussion of prescriptive grammar (prescriptive meaning the rules of how one should speak and write). So who makes the rules? Do these rule makers always agree? See the conflict lurking?
From Navigating English Grammar traditional prescriptive rules resemble table manners. You can eat your food perfectly well if you put your elbows on the table or chew with your mouth open. Many people do so all their lives. But if you want to join the local country club, watch out. Certain social circles expect you to follow the rules for table etiquette, and may exclude you if you violate them. Likewise, if you break prescriptive rules of language use, you will still be understood, but some may put you down as uneducated. Like table manners, prescriptive rules are imposed by an outside authority. Traditional grammar puts great stock in authorities. Something is right or wrong because a book or a teacher tells us so. But who gets to decide? Some countries have a central body, such as the Academie Franaise in France, which pronounces on disputed issues. Whether such academies have any influence on actual language use is doubtful, but in any event neither the United States nor any other English-speaking country has such a group. Instead, prescriptions about grammar are made by arbiters of usage. This group is not an organized body; rather it consists of anyone in a position to influence how other people use language: authors, editors, journalists such as William Saffire, writers of grammar textbooks and dictionaries. But those who have perhaps the greatest influence on the general public are classroom teachers. They are the ones who enforce the rules they believe are important when they correct student writing and speech. Even people who claim they don't remember, or never learned, any grammar in school can usually recall teachers with grammatical pet peeves who consistently criticized students for violating some rule or other.
Given the heterogeneous nature of this group, pronouncements on English usage vary widely from one another. Read any two usage manuals and you will likely find they contradict each other in many places.[Emphasis added] If you think about it, that's an odd situation. Prescriptive grammar begins with the assumption that there is a single standard form of the language which is correct. Why then can't the supposed experts agree? We're entitled to ask what criteria these authorities use to pass their own judgments.(from http://www.polysyllabic.com/?q=book/export/html/43 - no author listed)
It helps to remember that the history of English grammar, so long the poor relation of Latin, is hazy, ill-formed, and generally free of any heavy hand of authority. Spelling received the dictionary; grammar is still looking for that volume of the final say. Theres also the influence of geography: native users, forced users, and those that wanted a practical language for business have been sprinkled all over the globe. They picked up things.
THE VOICE OF HOPE RINGS FORTH ACROSS THE DEEP WATERS. Dont drown in all this; speak and write with common sense. The idea is to communicate effectively. You say or write exactly what you mean to say or write in a way the listener or reader gets it. Dont assume you know exactly who your audience is, though those letters in bottles turn up in strange places and times with YouTube coverage. Do your best.
ONLINE DEPARTMENT Wisdom from Grandpa (Thanks, D.W.) Whether a man winds up with a nest egg, or a goose egg, depends a lot on the kind of chick he marries. Trouble in marriage often starts when a man gets so busy earning his salt that he forgets his sugar. Too many couples marry for better, or for worse, but not for good. When a man marries a woman, they become one; but the trouble starts when they try to decide which one. If a man has enough horse sense to treat his wife like a thoroughbred, she will never turn into an old nag. On anniversaries, the wise husband always forgets the past - but never the present. A foolish husband says to his wife, "Honey, you stick to the washing, ironing, cooking, and scrubbing. No wife of mine is gonna work." Many girls like to marry a military man. He can cook, sew, and make beds, is in good health, and he's already used to taking orders Old age is when former classmates are so gray and wrinkled and bald, they don't recognize you. Keep laughing! It's good for you.