Confidence beyond all reason

I've been re-watching the Harry Potter series of movies (I'm currently on number 6) and was struck by the scene where Harry pretends to pour Liquid Luck into Ron's drink. Within the story, Liquid Luck allows the imbiber to luckily make everything happen in their favor--like a magical rabbit's foot. Anyway, Harry doesn't actually put the stuff in Ron's drink, so Ron's success is actually only due to being supremely confident. All he needed was a confidence boost.

But, my question is, if someone is trusting an outside agent (magic potion, object, person, or whatever) to the extent they don't believe their own actions are their own, then is it truly confidence or something else? Put the same person in the same situation again and I bet the result comes out differently (because the person knows the outside agent isn't actually responsible). I've seen this happen myself and struggle to explain it, especially in physical challenges (like Ron being brilliant at goal keeping in that movie). It's easy to say the physical ability already existed, but perhaps it's not that easy.

So, here's my question: when someone thinks they aren't in control, but an outside agent is doing it for them, is anything possible? Can things be done beyond the capacity of the individual? Confidence does many things, but it isn't magic and sure won't make anyone superhuman. Still, it's hard to turn aside the many examples that seem otherwise. Supreme confidence in my mind is a true magic trick--possibly the only real magic in the world. With it you can accomplish nearly anything. It's amazing to witness and even more so to experience personally. I believe, in the end, it isn't luck but you who make things happen.

- M