I've come to notice that too much of my time and energy is spent worrying about small problems in business:  among them being an intern not working hard enough, a small feature taking too long to build, a job candidate not working out, and other similar topics that don't have any meaningful impact on the future of inDinero.  Yet they seem to consume a disproportionate amount of my mind space, because these small issues stack up.

On the flip side, there are big problems that I should be spending 100% of my time thinking about:  Improving customer satisfaction, polishing product, hiring/retaining key hires, and making sure there's enough cash in the bank.  Most other topics are probably small, relatively meaningless, and should be ignored as quickly as possible.  

Whenever you're down about something, just ask yourself:  small problem or big problem?