I've read the book and watched the movie several times. I tend to agree with what Mojotec has spoken about. What you put out into your surroundings, is ultimately what you receive. That doesn't mean that if your 100% positive all the time, that you wont have a bad day. But if your motivated/goal orientated and have a general idea of where you are heading, then I believe you have a higher success rate at achieving what you want.
If you feel crap all the time and think the world is out to get you, I can only imagine that it would be hard to lift yourself up to think something positive could actually happen to you. No one is perfect. I don't know to many people that project themselves in a positive light 24 hours a day. But I do know a lot of people that give each day their best shot, and not to many of them are floundering in their lives. The biggest thing I think is that you create your own happiness. You cant obtain it from materialistic possessions or if you do, I'm not sure how you could retain 'happiness' for long. I guess the secret is really just common sense. If you decide to get out of bed positive and make an effort to being the best you can be, what do you have to lose?
Just my 2cents.
