Apparently you can OD on anything.

Mae West used to say too much of anything can be wonderful.

That said, I very much agree with this paragraph:

"When we are sad, we think in a more systematic manner. Sad people are attentive to details and externally oriented, while happy people tend to make snap judgments that may reflect racial or sex stereotyping."

If you're already happy and pleased with yourself, why keep trying hard?

Not everyone who's happy is pleased with themselves.

All of our most common moods/perspectives are here for a reason, each with their own strengths and weaknesses. We'd love to be happy all the time but there are definitely times where sadness, anger, and other less pleasant-seeming emotions are advantageous or signal different things to others.

For instance: want to appear competent? Happiness isn't the best way. Get angry.

Want people to think you're smart? Act like HOUSE and show some negativity.

Fascinating that emotions can be employed like tools in a toolbox to generate influence.

It makes me wonder if the difference between leaders and sociopaths is that leaders' emotions are for the most part authentic, whereas sociopaths pretty much just use emotions as tools for manipulation.

It's a fine line, most definitely. And some leaders are sociopaths. :P

I think this is why anger and negativity can be much more powerful signals -- they are "costly" signals.

Happiness is safe. Anger and negativity can alienate others so there is a risk associated with employing them (sincere or otherwise.) Because of the cost, we can trust them more.

More on the subject here. You also might want to check out the phenomenon of "stotting" in the animal kingdom which is a wonderful illustration of "costly signals" in nature.

I have never heard of happiness referred to as a safe signal before. That makes a lot of sense.

Anger and negativity are interesting signals for leaders to use, because you're right: they incur risk.

I think this is why a lot of leaders employ disappointment. All of the signal, none of the risk.