The second conditional and wishes

second conditional: The second conditional imagines something that is not true now, or is very unlikely: If I had more time, I would learn the piano. The shape is if plus a past tense, then would plus the bare verb — and the whole sentence is about the present.

distance, not time: This is the idea that makes everything else fall into place. The past tense here does not point backwards: it marks the sentence as unreal. English uses the same trick for wishes and for polite requests — the further from the present tense, the further from the facts, or the further from imposing.

I wish: I wish plus a past tense says that the present is not as you would like it: I wish I had more time means I do not have it. It carries a small regret, and it never takes would for your own actions — I wish I could is right, I wish I would is not.