You rarely hear complaints about people who overdo grammar. It’s much more common for people to be careless with subject-verb agreement, diction, pronoun case, and similar issues.
But I occasionally hear people using the subjunctive mood (that’s the grammatical term) when it’s not necessary. The word to watch for is if, and the question is whether to use was or were. (I’ve known people who use were all the time, just as I’ve known people who always use whom. Not a good solution!)
If your radio were tuned to NPR this morning at about 7:15, you heard an excellent report about Brexit. INCORRECT
If I were a British citizen, I’d already be feeling the effects of Brexit. CORRECT
Here’s what you need to know. The subjunctive (if I were) is only for situations that don’t exist. If something is (or was) possible, use was with if.
So…your radio really could have been tuned to NPR this morning. Use was:
If your radio was tuned to NPR this morning at about 7:15, you heard an excellent report about Brexit. CORRECT
Here are two more examples. In the first sentence, Joan really could have been in Florida during the hurricane: use was. In the second sentence, Joan isn’t going to stop being busy, so you should use were.
If Joan was in Florida last month, she experienced the full force of Hurricane Irma. CORRECT
If Joan weren’t so busy, I’d ask her to chair the committee. CORRECT