Grammar mistakes don't bother me much. I learned years ago that no one has perfect grammar and, especially in casual conversation, formal usage can be unnecessary — or even ridiculous. There's no better way to evoke eye rolls from new friends than to say, “For whom do you work?” or “You arrived earlier than she.”

Plus, even when grammar counts most, as in professionally edited books, mistakes happen. Some of my summer beach reads this year included mistakes like “We'll never know who's fault it was” (that should have been “whose”), “We won't know til tomorrow” (that should have been “till”) and “ice tea” (which should have been “iced tea”). All these typos occurred in otherwise well-edited books.

Some errors do bother me, but not the ones born of carelessness or human fallibility. The mistakes that make me sad are the ones that happen because someone was trying too hard to be proper and, unfortunately, didn't know how.

As I wrote recently, “I feel badly” is one such error. It should be “I feel bad” because linking verbs like “feel” take adjectives, not adverbs, as their complements.

But the most common hypercorrection I hear is “between you and I.” This expression garners about 57 million Google hits. “Between you and me” gets fewer than 5 million. That's just sad, because the grammatical choice is “between you and me.”

I suspect there are two reasons for the common mistake of “between you and me.” First, kids often get corrected, and rightly so, for using “me” instead of “I.” An utterance of “Emily and me are going outside to play” can evoke swift correction: “It's Emily and I,” a parent might say, “not Emily and me.” So it's easy to assume that “I” is always the safer choice.

The second reason I think people use “between you and I” is that they don't realize that this expression is not subject to the same rules as the “Emily and....” construction.

Either “Emily and I” or “Emily and me” can be correct depending on whether the phrase is functioning as the subject of a verb, “Emily and I are going,” or as an object of a verb or preposition: “The teacher congratulated Emily and me,” “Are you coming with Emily and me?”

“Between you and me” is different because “between” is a preposition and prepositions take objects. Always.

With regular nouns, this makes no difference. If you're writing “between jobs,” “with cheese,” “at noon” or “to the mall,” there's no chance you'll make an error because jobs, cheese, noon and mall don't change form.

But pronouns have both subject and object forms. I, he, she, we and they are subjects. Their object counterparts are me, him, her, us and them. So instead of “between we,” you would say “between us.” Instead of “with I” you would say “with me.” “At he” is clearly an error for “at him,” just as “to they” should be “to them.” In all these cases, prepositions demand that their pronoun partners come in object form.

“I” is a subject, and tacking it onto the end of “you and” doesn't change that. “You and I” is only OK when it's the subject of a verb: “You and I agree.” It can never come after “between” because that's a job for an object. Thus, saying “between you and I” is a lot like saying “between we,” which is clearly wrong.

If you like the sound of “between you and I,” no one's stopping you from using it. But if you're trying to use the language well, stick with “between you and me.”

JUNE CASAGRANDE is the author of “It Was the Best of Sentences, It Was the Worst of Sentences.” She can be reached at JuneTCN@aol.com.