From talking to my friends and just reading the news, I see that some people live life to one of two extremes. On one hand, you have people who breeze through life at full speed. They never look at the past and have no regrets over anything that happens.
The positives of living life at full speed is that they never worry about anything. They just do things as they see fit. These people are often confident (if maybe a little cocky or arrogant) that things will go right. Even if things don't go right, they just move on to the next thing.
The negatives are that sometimes these people don't learn from their mistakes. If these people are on the wrong track, then it may be difficult to steer them the right way because they don't stop to think about why things aren't working out.
On the other hand, there are people who do look back at the past but let it be a crutch. These people may have made mistakes which put them in tough situations but they can't get over the mistakes. Or they may have grown up in tough family or social environments and are unable to move past them.
You might say there aren't many positives in looking back but they are. For anyone to improve at anything in life, mistakes have to be made. I can't think of anyone who was able to do something perfect the FIRST TIME.
The negatives for looking back are fairly strong. For people who like to look back and analyze, sometimes when a situations or opportunities arise that need immediate action, these people aren't able to respond in such a quick manner. Thus there may be many missed opportunities in life.
Obviously, the majority of people don't live life to one extreme or the other. We tend to be centered toward the middle. There may be things we breeze right through without thinking about it. There will be other things that we take our time to look back to make an appropriate decision.
My point is that everyone needs to be flexible. Enjoy life but be willing to look back and/or listen to others if things don't seem to be going right. On the other hand, if you tend to look back, don't let previous situations or mistakes cripple your confidence. Every mistake we make will improve us more than we realize.