What does this mean?
A: What was I saying?
B: You were saying how much you liked spaghetti.

I don't understand what does s/he mean about "how much you liked spaghetti".
Did s/he like spaghetti, but now s/he hates eating spaghetti?
or
Is s/he talking about a spaghetti that s/he ate at a hotel or a restaurant?

Question

What does this mean?
A: What was I saying?
B: You were saying how much you liked spaghetti.

I don't understand what does s/he mean about "how much you liked spaghetti".
Did s/he like spaghetti, but now s/he hates eating spaghetti?
or
Is s/he talking about a spaghetti that s/he ate at a hotel or a restaurant?

Answer

"Talking about how much you like spaghetti" means "you were telling me about the fact that you really like spaghetti as a food in general"

Answer

If I understood properly,Person A said "what was I saying?"And Person B said "you were saying how much you liked spaghetti"So you want to know why Person B said "how much you liked spaghetti"?It seems Person A was talking about spaghetti but for some reason he/she forgot what he/she was talking about.So all Person B was doing was reminding Person A about what he/she was talking about. Person B wasn't making a statement about her/himself.

Answer

I would say that she likes in general, she always liked it... However all depends of the context of the conversation.

Answer

None of them. How much u like spagetti = spagettiyi ne kadr çok sevdiğinden bahsediyordun demek.