" Stress changes the dynamics of the conversation. When you’re calm and relaxed, your prefrontal cortex is pretty good at getting its way. But the more anxious or stressed you get, the more the power shifts to the dorsal striatum and nucleus accumbens. That’s why you might be doing fine on your diet until you get in a fight with your significant other. Or you might be exercising regularly until family drama raises its ugly head. When stressed, you usually act out your most deeply engrained routines or become a victim to your impulses. "

― Alex Korb , The Upward Spiral: Using Neuroscience to Reverse the Course of Depression, One Small Change at a Time