Recently, I've been enjoying reading about what are referred to as the 'natural laws' - the laws that govern the universe. It's pretty profound stuff, yet eminently sensible and logical.
One of the most compelling, yet slightly scary, laws is that of attraction. Simply put, what you think about most often is what you attract to yourself. If you think largely positive thought, you get largely positive results. And vice versa.
This article is worth a read, and if warranted, a recalibration of where your mind goes most often.