Ooh ooh, I got a great one!
Example: "We had some fights in the beginning, but now things are going great between she and I."
I just pulled that example sentence out of my butt, but it does illustrate a grammatical error that often happens. Just think, the person who wrote the sentence is patting themselves on the back, saying, "Yeah, I said 'she and I,' not 'me and her.' Ooh and I said 'I' too. So much more sophisticated than 'me.'"
I guess I'll give that person partial credit (for decorum), but what they should have said is, "her and me!"
Look, it's real simple. Try the sentence without "she," then without "I." See how it sounds.
"We had some fights in the beginning, but now things are going great between she."
"She?" Wouldn't the right choice be "her?"
"We had some fights in the beginning, but now things are going great between her."
And the same thing goes for "I." Not automatically correct just because it's "more sophisticated."
"We had some fights in the beginning, but now things are going great between I."
Between I? Bzzzt! Obviously not correct.
"We had some fights in the beginning, but now things are going great between me."
Notice how much more correct it sounds with "me" instead of "I?"
And that's why the truly correct sentence would have read: "We had some fights in the beginning, but now things are going great between her and me."
Your latest lesson is now concluded.