I don't know if this helps, but I often keep my ending secret (especially if I know it's going to have a major twist) until someone has read the entire draft in order to elicit a genuine reaction. If I've already told someone too much about the story, I don't know if I've appropriately prepared the reader for the end. I once gave two friends the same story--one who knew it was about a hurricane, and one who didn't. The one who knew thought I laid my foreshadowing on thick, and that any reader with a brain would know the hurricane was coming. The reader who didn't know said that when the hurricane hit, she was shocked--she never saw it coming. Knowing how a fresh audience is going to react is important to me, so I avoided telling that friend anything about the story until she had read it.

--Em