Not really. Let's say your key to happiness (something that does not come by often by any stretch) is here before you. You don't wanna fuck it up, but you know the chances of fucking it up are practically 99.9% by just trying to get this situation to work. If you know the odds of winning are like that of the lottery, then you know... you have something to be worried about. The worry about having to go on without the happiness, the future pain you know that it entails... You think, "If I worry enough. Maybe I will know something in that situation that can trigger some kind of very good series of synaptic firing that being otherwise non-nonchalant about would never see." That is really, the only reason why I get nervous.
you just said it.
you need to be CONFIDENT.
when your confident, the probability that you'll succeed goes substantially higher... when confidence is 0, the probability is horrible...
if you wanna compare it winning the lottery.... or say, charming a girl...
if you KNOW there's barely a chance it's possible, than that's it.. if your confident you have what it takes to woo said girl.. then your chances are way better.. this has to be really believed, because that is projected by your body language no matter what... and because body language hits us at a subconscious level.. she'll be woo'd, and not even be able to help it.. her reaction will be a reaction to your, "presence."
it's like holding the winning lottery ticket before you even know the winning numbers.