However it's not good to be positive all the time. In the chapter on Buoyancy, Dan Pink writes about a "golden ratio of positivity" which produces the best results. People who have an equal ratio of positive to negative emotions did not have any higher well-being than people whose emotions were mostly negative. Even those whose ratio was 2-1 positive-to-negative were no happier than those whose negative emotions exceeded their positive ones. The tipping point seems to be 3. Once positive emotions outnumber negative emotions by a ratio of 3-1, then people flourish. I thought that this was an interesting thing to contemplate when teaching students - keeping that ratio of positive to negative in mind when giving feedback, for example.
Finally Pink points out that there is an upper limit to positivity. Too much is as unproductive as too little. He writes that once the positive ratio hits 11-1 then the positive emotions start to do more harm than good. At this point, he claims, self-delusion suffocates self-improvement, so some negativity is essential. Negative emotions offer us feedback on what is working and what is not, and guides us about how to do better.
In my time in teaching I've come across people who don't believe that you should ever give negative feedback to students. This idea has always left me rather uncomfortable. In the studies that Pink refers to in his book this balance is seen in terms of levity and gravity, two competing pulls.
Levity is that unseen force that lifts you skyward, whereas gravity is the opposing force that pulls you earthward. Unchecked levity leaves you flighty, ungrounded and unreal. Unchecked gravity leaves you collapsed in a heap of misery. Yet when properly combined, these two opposing forces leave you buoyant.