when you really think about it, its just archimedes law of attraction, as well as some newtonian principles, applied in a social framework.. why positive attracts positive and negative attracts negative only has to do with the theory dealing with thought manifestation itself, that whatever culmination of thoughts, images, and associated feelings there are etc, will be brought about to reality by your own mind.. in other words if say there is love in a thing, or even hate in a thing, whatever it will be, it will be your own creation..but I digress, nobody is suggesting that if you think something truly sorrowful, that your thoughts will be manifested as something positive, or visa versa, that would be absurd to the proponents of this theory, however it somehow doesnt account for the seemingly beautiful works of art that have been created out of great misery and suffering, nor does it explain the social hypocrisy that exists in the so called positive visualizationists ideas.. ..its easy when you have privilege or you are a member of the ruling class to tell some poor single mother slaving away at a wallmart or someone in the grape fields to excercise positive visualization etc...

A wise man once said to me "if you sleep with dogs you will probably get fleas"

It's the same way that when you're in a great mood and your boss walks in and reams someone out in front of you- your mood suddenly disperses, and you're left feeling uneased. It's also in the same way that when you're feeling the day to day rush making you logy, and someone in the supermarket says "Isn't it a beautiful day? I'd like to take the kids out to fly a kite. You look like a kite flier- you have that look in your eye that tells me you enjoy the little things." It doesn't matter if you actually fly kites, or even can tolerate it. Their positive mood and energy revitalized you, and you will walk away smiling, likely thinking about them on your way home.