The theory is that your thoughts create your reality, so one must keep eternal vigil over them to avoid drawing negativity into your life. You must think clear and positive thoughts all the time, and think about yourself as nothing less that worthy and deserving of the very best. My experience is that if this worked in real life, the Cubs would've won the World Series and Sting should be calling to beg me to do a duet version of "We'll Be Together."
Does this mean that someone who follows this philosophy gets punished if they're having PMS or some other physiological problem that might life seem a little less than rosy? Does this mean that the people of Darfur and the women of Afghanistan brought their misery on themselves? It's hard to be positive on a chronically empty stomach with gunfire going off in the background or when you can't leave your home unescorted for fear of beatings.
I'm sure they don't sit around questioning what they are doing wrong to block their highest good. No one has that kind of power, darlings.
We can delude ourselves to an extent, and we can choose to see the glass as half-full or half-empty. But when all is said and done, isn't this just another expression of fear? Fear that we won't have our needs met (needs, for wants are not necessarily in one's best interest), fear of relinquishing perceived control over the flow of life.
A workshop that I heard of taught participants that using words such as "can't" or "don't" as in "I don't know" would block their good from coming to them. I tried crafting spoken sentences using the guidelines. That lasted about two minutes. I didn't like feeling as if I were damming and stilting the flow of my life in the name of something that will never be.