What does "America" have anything to do with this? You could complain all day long about how bad of a situation you are in, or you could do something about it, and that's a fact.
How is something as common as "positive thinking" unique to American? I don't understand how you picked up that idea. It's like saying "being courteous to elders" is uniquely Chinese.
It's generally assumed that positive thinking is how you get ahead (another American belief), but that doesn't seem to be the case: http://www.newyorker.com/currency-tag/the-powerlessness-of-p...