Life is all about making choices.
When I was still in grade school, I used to read a book that would have you decide what course the hero would take. Naturally, the book contained a couple of possible endings depending on the choices that you make---you can either end up triumphant or a failure. Since it's a book I had the chance to go through all the possibilities.
In real life, however, we only get one decision for every situation. The hard thing about making a choice is accepting the outcome---this is specially true if the decision made was not to our liking. The thing is, a bad decision should not be followed by the worst decision of deciding on just to sulk at "what should have been".
There should never be a place for REGRET in life! It's counter productive and it pollutes the mind! The important thing in life is to have the ability to pick yourself up every time you fall and find the courage to move on. Failure should be viewed as an opportunity to do better. I'm sure you have heard of the saying "try and try until you succeed". In like manner that we should go about living life!