Outside of undue physical or emotional pain beyond the everyday aches and pains of normal living, it seems that unhappiness comes from wrongful thinking. People seek the guidance of a therapist to point out what is causing their wrongful thinking in the hopes of correcting the way they think. The path to happiness, then, is in changing how we think. This is something only we can do. If we eliminate the step of finding the "cause" we can simply work directly with changing the thinking. In other words, we should be able to achieve a higher level of happiness by thinking "happy" and actively seeking happiness in ourselves. This would not be a fixed level but more like an oscillating level of highs and lows, but at a higher base.
If happiness is always due to forces completely beyond our conscious control then we are doomed to sit back and wait for these forces to make us happy, and seeking relief from our miseries is completely useless. I believe it is possible to "force" ourselves to be happier. Anyway, I think I'll put the theory to the test.