I do believe in it, it's like positive thinking has a positive impact on your life, You have to believe in yourself to succeed, to give yourself a chance..
if you keep on telling yourself no I can't do it, I won't do it, I will never succeed, of course you are going to believe that and that is what will happen as you made that happen..
Did you ever meet a really negative and down person and there is no talking to them.. no matter how you try to spin a positive vibe for them they won't believe it and pretty much say.. no my life sucks, it will always suck... I am doomed...
Well I believe their negative thinking keeps them stuck the way that they are.. it's certainly not going to help in any way whatsoever.