Please no confirmation prompts. Those are annoying when I am sure that I want to perform an action. I'd rather have an undo button after clicking.
On the other hand, maybe it's a feature. Lately I've taken the approach that if I hid it accidentally, it probably wasn't worth reading anyway. I'm learning to let it go.
Edit: HN does in fact have things that change without reload like voting, so I take that back, good idea