Gallup polls on a number of kind of, well, random sentiments. Among them is this poll on whether or not people would categorize themselves as "energized" or "ailing". Frankly, I'm amazed that 30-40 percent of people always consider themselves to be "ailing", but more peculiar than that is the constant back and forth chop in the numbers. Given that these changes reflect net rather than gross changes in each category, I'm amazed that as much of the population swings back and forth as it does.
I would be curious to see, all other factors being held constant, if you line up these numbers with stock market performance on a day to day basis if there would be any relationship.