I have extensive background both as a Russian and as an American; and one issue on which the two populations have historically clashed has been outlook. Russians are pessimistic, and Americans are optimistic. I've had the influence of both.
I have come to the conclusion that there are both virtues and flaws with each. Optimism gives you the positive attitude that you need to make things happen; it also overlooks critical information and makes foolish mistakes. Pessimism correctly anticipates possible problems, but it lacks the drive and the attitude to solve them. The correct solution is a mix of the two. Have optimism to make things happen while being careful and anticipating what can go wrong.
Sometimes ideologies come to pander to moods. We have the New Agers claiming that positive thinking is the solution to everything. It is no such thing. Positive thinking by itself causes more problems than it solves. You think positive, you fail to anticipate problems, you do foolish things. It is valid to encourage the attitude that one is up to life's challenges, not valid to encourage carelessness or shut away legitimate criticism of one's actions.
Similarly we have people who have no use for spirituality whatever. Also wrong. I have had many experiences with less than a billionth chance of happening whose only possible explanations are spiritual, and I am far from the only one. Some people with such beliefs consider themselves the only sane and rational people on the planet. I can think of no greater hubris than that.
One conflict that is hard to resolve is that of what goes on at different levels. Some think that thoughts affect things at the quantum level; and of course if that is true then your state of mind matters. However it does not mean that you are creating your reality with your thoughts, and it most certainly does not mean that positive thinking is good and negative thinking is evil. However positive you get, if you cut down the rainforest it has been cut down, and no amount of positivity will change that outcome. Paying attention to such things is not being negative or whining or blaming. It is called having a conscience. There is what you do with your thoughts; there is also what you do with your actions. And, as we see with the rainforest situation, they clearly talk louder than thoughts. However positive the Japanese Buddhists get, when a reactor blows up they have to tell what had happened. Anything else is not enlightenment, it is lying.
If, as some believe, positive attitude creates winners and negative attitude creates losers, then there was no way that Soviet Union could have credibly rivalled America for leadership of the world. They should have been complete losers; instead they became a superpower. Positive attitude can be attractive to other people and as such improve one's prospects; but in no way is it a prerequisite for success.
On the other side is the attitude that positive thinkers are nitwits, or that being negative is an intelligent attitude in face of what we know of reality. Some people think that we are on an entropy express, and that we can only lose. That too is incorrect. Some things about the world are depressing, but there are many things that are good in the world, and many people have done valuable things in the world. Being depressed is not the same thing as being intelligent. The cause for happiness in the world is this: Man's will. And that means man's ability to solve problems or come up with new and valuable things.
So let's keep what's right in each and discard what is wrong in each. With optimism, keep the can-do attitude while discarding the carelessness. And with pessimism, keep being cognizant of possible problems while discarding the helplessness and negativity. And then become a force for actually solving whatever challenges we have to face without either denying them or thinking them too big for us to solve.