Those of you who have browsed among these posts have seen repeated mentions of the superstitions, shibboleths, crotchets, and schoolroom oversimplifications to which language peevers resort. I thought it might be useful to compile a more or less comprehensive list of them.
I append no explanation of the fallaciousness of these imagined rules of usage, which Arnold Zwicky famously labeled "zombie rules." For those of you who are startled to find here things that you thought were rules, you are not to blame for having been badly instructed by a teacher, professor, or editor. Consulting Merriam-Webster's Dictionary of English Usage or Garner's Modern American Usage will turn up explanations of the realities of the language with which you can inform yourself.
While you can't fix stupid, you can remedy ignorant.
If you are observing any of these bogus rules, pray stop now. Just stop. Right now. I'm talking to you.
Item: The dialect called standard written English is the standard of the language, and all variations from it are substandard, uneducated, worthy of contempt.
Item: It is wrong to split an infinitive.
Item: It is wrong to split a compound verb by inserting an adverb between the auxiliary and main verb.
Item: It is wrong to begin a sentence with a conjunction such as and or but.
Item: It is wrong to end a sentence with a preposition.
Item: However must be used only as an interjection, not to introduce a clause.
Item: Hopefully may not be used as a sentence adverb.
Item: None may only be used as a singular.
Item: Singular they is impermissible.
Item: It is wrong to use since to mean because.
Item: It is wrong to use over to mean more than.
Item: It is wrong to use convince to mean persuade.
Item: It is wrong to use loan as a verb.
Item: Between cannot be used for more than two objects.
Item: That cannot be used to refer to human beings, only to animals or inanimate objects.
Item: Data and media can only be used as plurals.
Item: Decimate can only be used to refer to a reduction by one-tenth.
Item: Only must always be placed next to the particular word in a sentence that it modifies.
Item: Collide can only be used when two objects in motion strike each other.
Item: It is wrong to use which to introduce a restrictive/limiting/essential clause.
Item: Passive constructions must always be avoided. [Frequently combined with an astonishingly ignorant belief that any construction containing a form of to be is a passive.]