You're Driving I Crazy!
Remember that 8th-grade teacher who scolded you when you said, “Me and my friends”? If your teacher was like mine, then she kept correcting you - “It's my friends and I” - until she drilled it into your head and now you can't say it any other way without twitching a little. Unfortunately she was right... most of the time. After all, this wouldn't be English if it wasn't needlessly complicated.
Sometimes it's incorrect to say, “[So-and-so] and I,” and you have to say, “[So-and-so] and me” instead – even if it makes that nagging voice reappear, wagging its metaphorical finger at you. If you're talking about something that's happening to you and to others, then chances are you need to use “me,” as in, “They're throwing a party for my friends and me!” or, “That family vacation was a nightmare for my parents and me.” If this seems wrong to you, imagine these statements with the other people taken out of them: “They're throwing a party for me!” Pretty intuitive, right? Now try it the other way: “They're throwing a party for I!” You don't have to teach 8th grade to realize that doesn't sound right.
A similar rule applies if you are the one performing the action. You don't say, “Me and my cousin are going to the lake” because if you were to remove the other person (sorry, cuz), you'd be left with, “Me am going to the lake,” and that's clearly not right. That's how cavemen talk in bad jokes.
What we're looking at here is the distinction between subject and object – who “gives” the action of the sentence vs. who “receives” it. When you're the subject, you are “I,” as in, “I hope the Beltway isn't totally jammed today.” But when you're the object, you're “me,” as in, “Grammar drives me crazy!” This is why it's okay to say, “It's high time I did something for me for a change.”
And you know what? It is. Go ahead, do something nice for yourself. Because once you get all these little nuances of English mastered, you're going to sound more professional – on the page and in person – and that's going to take you places. It might seem like a stupid little rule to get caught up in, but it will pay off when you're dealing with the type of person who values these things. It just so happens that many of them are employers. So go ahead and congratulate yourself – you're one baby step closer to getting hired.