I really found your list helpful. However, one culprit needs to be exposed. Was-were. The only thing I remember learning as a clue was: 'if' demands a 'were'. Could you comment on the rules?
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Good to hear from you with this classic question.
Old grammar rules stick in our minds like chewing gum in the hair. The rule you remember is no longer a rule (perhaps it never was) but a choice. I tend to use ‘were’ out of habit myself, but 'was' is now more than acceptable—it’s the norm. The Style Manual (Commonwealth of Australia 2002 edition) explains a logical flaw in the original rule, and says:
In Australian English the ‘were’ subjunctive is falling into disuse, replaced by ‘was’ for ordinary purposes. This then makes the ‘were’ subjunctive a distinctly formal choice in terms of style.
I love the Australian Style Manual for its clarity, layout and index, and because it’s up to date. It’s worth noting that the Yahoo Style Guide, Economist Style Guide and Fit to Print don’t even bother to mention this rule—it’s a non-issue.
That’s the way it happens! The first grammar rules we learn are more than likely unreliable even at the time, but they stick tight in our brains like old chewing gum.
So we can carry on using were after if, but have no reason to blame others for using was. It's annoying, isn't it?
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Image by Jared Eberhardt, CC BY-SA 2.0. "I smashed gum into his hair in the hot tub and it sort of melted to his scalp where my dad had to shave it out.