From a conscious perspective there is a lot to be said for having a sunny disposition, and everyone knows that there is nothing that beat the rosy hue of a positive point of view.
Though the notion of feeling good may sound like elusive ideals in the minds of most people I know there is more than enough evidence that happiness is a presumption within everyone's reach, not to mention how much objective proof there is in the proverbial pudding. But with reason being the ultimate objective, you'd be surprised how little people seem to care to change for the better.
For those who can admit to the possibility that that their view may be biased, and willing to try something new there is more than enough evidence to satisfy the curious, and if you are serious about knowing more there are even graduate and post-graduate studies available on the science of being happy.
So next time you find yourself in a bad mood ask yourself this: "Why?". If you can come up with a good enough reason, remind yourself that your mood is clouding your reason, limiting your perception, and confusing your perspective, whatever the reason.
Have a nice day!