Do you too make these two annoying grammatical mistakes?
No, not the usual there vs they're vs their. I know you can spell. The intriguing thing about these two is that they tend to be made by highly educated and grammar-conscious individuals. So here is a quick refresher.
Straight to the point: the first one is I used instead of me in sentences like Here is a review of a paper written by my assistant and I. Turns out you can be a published author or a professor at a world-class university (or both) and still be confused by this subject vs object distinction.
Meanwhile, it couldn't be much easier to figure out which option is right. If in doubt, simply remove the buddies that accompany you in that sentence, then re-introduce them without changing the preposition that describes you. There's clearly no way you'd say Friends are coming to visit I, so you only need to remember that the subject remains a subject when somebody else joins you: Friends are coming to visit my spouse and me.
The second one is a bit more tricky – and, predictably, more widespread: it's the conditional perfect (would have been) after if or wish. It surely sounds more sophisticated than a simple had, but it's wrong.
When it comes to conditional sentences, there are basically three options to choose from:
If I meet a zombie (in the future), I'll bite off his head. (Better safe than sorry.)
If I met a zombie (I haven't so far, but if I did...), I would bite off his head.
If I had met a zombie (in the past, when they were still around), I would have bitten off his head.
That is essentially all there is to remember. There can be variations in terms of continuity (If I had been sleeping that night, I wouldn't have heard the zombie enter the house) and passive voice (If his head had already been bitten off, I wouldn't have had to bother), but the point stands: there can be no conditional tense in a conditional clause.
This applies to wish sentences, too. Wish you were here (right now)? Yes. Wish you had been here (last week, when I single-handedly saved the world from a zombie attack)? That's right. Wish you would have brought a TV crew, too? No. Mostly because the conditional perfect can't be used in a sentence like this.
Will you remember that now?
If you would have asked my friends and I to mow your lawn for free, we would have happily accepted.
If you had invited my friends and me to the party, it would have been much more fun.
You know which of the two is correct, right?