Most of us do it unconsciously and don't recognize why, or know how to stop it. It's not always brownies, that's just my snack of choice. Some people call it procrastination, some avoidance, some a habit, and it can be all of those.
What is really is, is your personal form of self-sabotage - a way to make sure that the dreams you have, the goals you've set, the experiences you want to create don't happen, or if they do, their success is short-lived.