Two pairs of words that cause confusion:
If you reproduce someone’s exact words, such as ‘Martyn Beardsley’s new book Murder in Montague Place is the best crime novel in years’…
…then it’s a quotation not a quote. The words are something you quote, but the thing you are quoting is a quotation. Clear? The problem is, so many people use quote as a shorthand version of quotation that we’re getting to the point where it hardly matters. In ye olde days dictionaries used to be the place we could turn to for the Truth, but these days they are so keen to be cool and with it that they cravenly give in to such trends. You will often come across phrases in dictionaries where they give the incorrect version as an alternative, with a proviso like ‘often used as…’ Dictionaries shouldn’t care how a word is ‘often used’! They should just tell us how it should be used!
The other pair of words I’ve personally always been less clear about, at least in certain contexts. This is my explanation, but I’m open to offers! When you check your bank account and see there isn’t a lot left in there, you would probably say, ‘I might buy Martyn Beardsley’s captivating Murder in Montague Place…’
You are in control of the decision and the outcome. But if you hear that it’s such hot stuff the shops are selling out, you would set off saying, ‘I may buy the book…’ because you don’t yet know whether it’s going to be on the shelves or not even though you fully intend to get it.
So might, in my little world at least, is for something over which we have control. May is used when the outcome is uncertain or can’t be known at that point. I might watch that programme about the Kennedy assassination. He may have been shot by someone other than Lee Harvey Oswald. (Although that’s perhaps a bad example, since he clearly was shot by someone on the grassy knoll…)