Long ago, mystics and spiritual people in India realized that positive thinking actually works miracles. Your thoughts actually go "out" there [1], to get you what you want. The more your belief that it will happen, the higher the likelihood of it happening.
However, in India, the general public doesn't like any kind of mental exercise - be it thinking or mind related, (e.g. meditation). And so the mystics had to trick the public into positive thinking. And this benefitted them in MANY ways ....
The public would be asked to do some complicated ritual/havana/puja, or take a hike to some distant spot to solve a problem. This tricked the individual into thinking positively - he believed that the ritual would heal him, or solve the problem. If his belief was good, it worked.
The benefit the mystic got through this was that a dependency was created between the 2, and he could now control the individual. A mystic will NEVER talk about the power of positive thinking, because it FREEs you of him. He/She wants to control you.
When this worked, then new forms of rituals came out. If you could "donate" a large sum of money to some temple, you would get huge amounts of "grace", or your wishes would come true. So now the mystic even makes big money, by making you buy positive thinking! In India, people donate unthinkable amounts of money to temples (usually black money if you are rich, but for the average person, it is very hard-earned money).
Imagine, making God into someone who sells His "grace". Imagine the One who created this entire universe, who IS this entire universe, actually needs something from you, in order to let you live happily.
I know what happens in this country (India) in the name of God, gets me into "rant" mode, so let me take a deep breath and back out, and summarise.
1. Positive thinking works, and you should be in this state all the time. If you believe in God, it becomes very easy, since you see His hand in all things.
Avoid negative thinking, because that also works - against you - something that mystics and astrologers also use, to draw you to them.
2. Positive thinking gives you freedom from others, which is what they have been trying to take away from you. They wish to control you.
3. Positive thinking is FREE. Why buy God's grace when you get it free. Why pay some half-witted trickster, for something that is your right.
[1] - remember that the universe is in the mind, not out there. So the mind can change it.
