Most Spanish speakers learn early on what the difference between “some” and “any” is. “Some” is generally understood to be used in affirmative sentences while “any” is used in questions and negative sentences as in the following examples:
Is there any time left?
There aren’t any people in the lobby.
We have some books.
However, these very general rules don’t cover all the times that you would use either “some” or “any”. Take a look at these two questions:
Would you like some water?
Could you give me some advice?
If these are questions, why do we use “some”? In requests and offers, we don’t use “any”, we use “some”.