There's a difference between me and I.

In casual conversation, most people I know don't worry too much about sounding proper. They don't bother with "whom." They say, "There's a lot of people here" instead of "There are a lot of people here." They opt for forms like "Joe is taller than me" instead of "Joe is taller than I."

But there's one situation in which it seems everyone is bent on sounding as proper as possible. Consider the sentence "I'm so happy you were able to spend time with John and I." Choosing "I" over "me" in sentences like this seems to be the preferred form of practically every English speaker with even the slightest interest in sounding educated.

Unfortunately, in this case, trying to sound like you have good grammar makes things worse because the grammatically correct form is "with John and me," not "with John and I."

I have a theory about why this hypercorrection is so common. When kids say stuff like "Katie and me are going outside" or "Kevin and me are playing video games," many parents are swift to correct them. Kids assume that "I" is more proper than "me."

But that's not always the case. If you really want to sound like you know your stuff, you need to understand the difference between subject pronouns and object pronouns.

I, you, he, she, it, we and they are subject pronouns. They perform the "action" of the verb. I walk fast. You work hard. He is nice.

But when they function as objects, most of these personal pronouns take different forms. Me, you, him, her, it, us and them are object pronouns. "You" and "it" are the oddballs, functioning as subjects and objects.

Object forms are used when the pronoun is a direct object of a verb, as in "Get to know him," or as an object of a preposition like "with," "at" or "of," as in "Go with him."

So the parents are right that it should be "Katie and I are going outside" because in this sentence "I" is a subject. But when the pronoun is functioning as an object, "I" is wrong. "Watch Katie and me" is the right choice because the pronoun is an object of the verb "watch." "Play video games with Kevin and me" is correct because the pronoun is an object of the preposition "with."

If you're worried you'll forget that, there's a simple test to ensure you always get these right: Just ditch the other person. You would never say, "I'm so glad you could spend time with I." You would never say, "Watch I." Just by getting Katie and Kevin out of the picture, we see clearly that these sentences call for an object, not a subject.

That doesn't change just because Katie or Kevin shows up. With or without another person, the rules about subjects and objects hold true. It's just that when we throw in another person, it conjures up the mislearned lesson from childhood that "me" is safest when another person is involved.

So now that you understand subjects and objects, here's a little quiz for you: Which is correct, "between you and I" or "between you and me"? Here it's not quite as easy to just drop "you and" because it doesn't make sense to say something is between one person. But you swap out the pronouns for another subject/object combo: we and us.

Noting that "we" is a subject and "us" is an "object," ask yourself, is it "between we" or "between us"? Because the subject pronoun "we" doesn't work here, we know that the preposition "between" requires an object like "us." And because "me," like "us," is an object, the grammatical choice is always "between you and me" and never "between you and I."

JUNE CASAGRANDE is the author of "The Best Punctuation Book, Period." She can be reached at JuneTCN@aol.com.