Araban wrote:You can be the happiest or the saddest person in the world, but the goban and the stones won't share your feelings. In other words, I think maintaining positive morality is neither essential nor the reason why players crack and fall behind from a winning position (the answer to the latter is usually carelessness). Instead of maintaining positive morality, I think it's more important to maintain a high level of concentration. Put more faith in your reading, not in your emotions/mental state.
...Oh, I hate myself for doing this...(chalk it up to OCD of some form or other) "positive morale"
But I think morale can have a huge effect. A high level of concentration is extremely important, but I don't think human beings can completely separate their feelings about a position from their analysis by simply concentrating.
I think good morale makes concentration easier, and likewise, bad morale will limit your ability to concentrate. Your reading will be better/deeper if you're feeling better. Many tomes on military strategy have huge sections devoted to morale (see Sun Tzu).
As long as you're a member of the human race, your excitement, or lack of, will affect the way you play. If you learn to control it, you can indirectly improve your concentration.
EDIT: To paraphrase Sun Tzu,
Concentration is a matter of emptiness and fullness. A full concentration vs. an empty one is like rocks thrown at eggs