This appears to me to be an extension of the old, "You are what you eat." Sure, there are lots of us who greet each day with continually diminishing enthusiasm. Certainly this is a reflection of our mindset. Perhaps one of the more tragic problems some folks experience is to have brains that cannot perceive the world in other than negative ways. It isn't their fault. It is the manifestation of how much their body chemistry has become out of whack (to use a medical term.) Sometimes medications help to restore chemical balance and sometimes they don't.

It is my belief that some of the things that trigger the chemical imbalance in the first place might have roots in a person's inability to find something positive in their lives upon which to focus. Instead, each time something goes amiss, the response pattern that eventually evolves allows no vision beyond the problem.

I strongly believe that if a person sets up a pattern of finding positive things in their world, problems, no matter how difficult, will not become the only focus. Those people who can teach themselves to extract pleasure from even the smallest of things might never lack for defense against depressive forces.