Being the president of one of the most powerful and influential countries in the world is no easy task. Difficult decisions must be made, and presidents are only human, so mistakes happen. One might say it's part of the job, but sometimes things really go wrong and presidents feel the weight of regret.
There are a few US presidents who expressed regret over a number of things. Some did so while still in office, while others confessed it later in their lives. In this gallery, you'll get to know who they are, and what they've regretted. Click on for some eye-opening revelations.