9 Sneaky Reasons You're In A Bad Mood (And What To Do About It) There are lots of reasons to be in a less-than-stellar mood. Strained relationships, financial woes and health problems can all conspire to bring down your mental well-being. For factors like these, we have very little control or say over the outcome. But fortunately, there are a few small things you can change in your life to give your mental state a little lift. Below, some potential hidden reasons for your bad mood (and how to remedy the situation STAT): 1. You're not getting enough fruits and veggies.