In our lifetimes, each of us faces decisions, large and small. The large decisions include choosing jobs and spouses; but we also have to choose what to eat for breakfast when we first wake up. Unfortunately, even the most carefully made decisions can leave us haunted with feelings of regret, or "what if?" Many of us carry these feelings of regret with us over time, allowing them to influence our future choices.

Of course, regret isn't necessarily a bad thing. A person who regrets drinking too much at a party or treating a friend badly may learn not to make these mistakes again. In this instance, regret helps the person make better decisions in the future. Some people live by the mantra of "no regrets," but this too can be a bad idea. Without regrets, you'll never learn from your decisions, which leaves you doomed to repeat past mistakes. On the other hand, too much focus on regret can lead to paralyzing fear. If you constantly focus on your past mistakes, you may begin to doubt your ability to make choices, which can prevent you from making any choice at all when faced with a decision.

Scientific studies show that people tend to overestimate the level of regret associated with a decision, and that the majority of people regret inaction above all else [source: Connolly and Zeelenberg]. When faced with a hypothetical decision, study participants believe that they are much more likely to regret things they do than things they don't do. When asked about real-life experiences, however, an overwhelming majority regretted the things they hadn't done much more than the things they had.

More recent studies show that people anticipate much higher levels of regret than they actually feel when making decisions. Participants on average felt less regretful about failures or bad decisions than they expected, and those who made the most reasonable and informed decisions experienced the lowest levels of regret.

So, what's the answer to balancing regret with effective decision-making? First, take the time to learn from your mistakes. Consider the experience a lesson learned, but accept that you can't change the past. When it comes time to make a choice, acknowledge your fear, but trust yourself enough to push past it. Above all, remember that many of the things you fear are unlikely to occur, and that the greatest regret lies in a failure to act.

When we make decisions, we're heavily influenced by the ghosts of decisions past. Bad decisions we've made in the past influence our present brain activity when we're presented with a choice. Any choice prompts heavy brain activity in gray matter responsible for emotion and emotional memories -- namely, the medial orbitofrontal region, the anterior cingulate cortex and the hippocampus. The higher the stakes, the more activity experienced by these parts of the brain. For this reason, researchers believe we're less motivated by the opportunity for gain than we are by the fear of regret.