Difference between "You and I" and "You and me"

A student by the name of Ogi asked about the difference between "You and I" and "You and me" at today's lesson. And I promised to post it here. So:

Grammarwise:
You and I went to the store.
Not “You and me went to the store”.
Because I here is the Subject of the sentence.


Keep it only between you and me.
Not "Keep it only between you and I".
As I mentioned earlier at the lesson, me is grammatically correct after verbs or prepositions (as an object)


But in modern spoken language, it is still okay to use them interchangeably although some grammarians want to hypercorrect everything :-P

Always follow the rules when you're taking an exam!
When you're speaking though, don't try to look nerdy :D

Alright, feel free to ask me more ;)