(with examples from The Sentinel, Firefly, and Saiyuki and general guidance from The Gregg Reference Manual and Garner’s Modern American Usage)
One of the most common errors made with I/me is thinking that anytime someone else is mentioned first, we should use “I,” so we end up incorrectly writing things like “Talk to Jim or I about that.”
I’m convinced this is a hypercorrection from our childhoods. Remember your six-year-old self, having concocted the most deliriously wonderful scheme, rushing indoors and asking, all in one excited breath, “Canmeandjennygotothepark?” only to be rebuffed with a stern, authoritative, “May Jenny and I go to the park!” It seems a lesson many of us took too much to heart. While Jenny and I go to the park, Mom goes to the park with Jenny and me.
So what’s the difference between “I” and “me”? They’re both first person singular pronouns; where they differ is case. “I” is the nominative (or subjective) case, which means it’s used as the subject of a verb — that is, the thing that is acting or being — or after a form of the verb “to be.” There’s more to that second one, though, which I’ll address later.
Meanwhile, here’s an example of the pronoun “I” as the subject of a verb:
Jim: I am not going to be some human lab rat for you to prod and probe every time something goes wrong. (The Sentinel, “The Killers”)
Please note, it does not matter how many people are performing the action or sharing the state of being, the pronoun case does not change.
Jim: These men and I have held the Chopec Pass for 18 months. And quite frankly, Captain, I'm kind of tired. (The Sentinel, “Switchman”)
If in doubt, remove everyone except the speaker from the equation. You would say, “I have held,” not “Me have held.”
While “I” is the nominative case, “me,” is the objective. See that word “object” in there? A pronoun takes the objective case when it is (1) the direct or indirect object of a verb, (2) the object of a preposition, or (3) the subject or object of an infinitive. Sound like a bunch of mumbo-jumbo? Here are some examples from Firefly.
Inara (“Out of Gas”): You want me. You want me on your ship. (direct object)
Kaylee (“Out of Gas”): You offering me a job? (indirect object)
Jayne (“Jaynesville”): There ain't people like that. There's just people like me. (object of preposition)
Wash (“Out of Gas”): What do you expect me to do, Mal? (subject of infinitive)
Inara (“Serenity”): Would you like to lecture me on the wickedness of my ways?
(object of infinitive)
Just like with “I,” “me” is used whether the object is one person or more than one.
If you have any questions, just ask Simon or me.
And just like with “I,” an easy way to test which is correct is to remove the other people from the sentence: you would say, “just ask me,” not “just ask I.”
The same rules apply to the first person plural personal pronouns “we” and “us.” “We,” like “I,” is nominative case and should be used as the subject of the verb, while “us” and “me” are objective and are used as the object of the verb or preposition, or the subject or object of the infinitive.
Watch for clauses or phrases that serve as the subject of the sentence but contain a personal pronoun. In the sentence “For me to go in there would be dead wrong,” even though the pronoun comes before the verb, the pronoun is not the subject of the verb; rather, it is the object of the preposition “for,” so you would use “me,” not “I.”
Than I/Than me?
There’s some lingering dispute whether to use "I" or "me" after “than" in a comparison. While the formal usage demands “I,” many people consider it acceptable to use "than me" in speech and informal writing. You can sometimes sidestep the issue by adding the understood verb.
Jim: Nobody wants you to be right more than I do. You wrap this up today, I'll pin a medal on you myself. (The Sentinel, "Private Eyes")
And that brings us to the other arguable usage, the one I mentioned earlier, using “I” after forms of the verb or verb phrase “to be.” Frankly, very few people do this correctly, and it can sound incorrect and jarring when they do. Consider:
Blair: Oh, no, it wasn't me, Jim. (The Sentinel, “The Debt”)
If he were speaking correctly, Blair would have said “Oh, no, it wasn’t I, Jim.” But not many people talk like that. Consider character voice. First person means the character is speaking or you’re in the character’s head. Would that character use uncommon but correct grammar, or would they use common idiom?
This applies to all of the rules above. The more educated, formal, and precise in speech a character is, the more likely they are to correctly use “I” and “me.” In Saiyuki, Hakkai, a former schoolteacher, would refer to “Gojyo and I.” Gojyo, who was abandoned at a young age to fend for himself, would be much more likely to talk about “me an’ Hakkai.”
Know the rules, know when to break them, and if you reflexively tense up every time you start to write “and me,” tell your six-year-old self that it’s okay, you know what you’re doing now.