I love that article. Haha. And I have known that stuff for a long time. Actually part of our culture, undilute optimism, constant smiles, exaggerate friendliness is considered as something rather shallow in Germany. We love the deep digging, dark, gloomy stuff. ; ) And anything uncritical is considered as just that- in other words, a little stupid.

michael - I wondered about that myself but from reading the article about the study it seems that it isn't so much that grumpy people are better thinkers but that we all tend to think more clearly/realistically when we're grumpy (no matter our basic outlook). The article is also pretty clear that being optimistic is the source of other very needed qualities of thought, including creativity. Grumpy is good for editing processes but it's not really that good for the initial creative stages of a project it seems (and my experience bears this out but I may just agree because I have a confirmation bias acting up). Pessimism is no more realistic than optimism really, and it's a bit hard to tell how they're really defining each state/mood/attitude. I mean, there are plenty of things about the world that are unpleasant but it's also filled with beauty, love and all kinds of pleasant things too. I'd suggest that we see the world and situations most clearly when we're not actually putting them in an emotional light (being grumpy or optimistic) that casts either a negative or positive light on them. Things are what they are but our human brains like/need to discern/judge them as good or bad and it takes practice to be able to get beyond that even for a little while (not that emotions don't play a critical role in the decision making process and aren't useful, they're just innately subjective in the light they cast on something).