It is common place to reminisce about the paths you didn't take in life, about your "lost opportunities" as a result of the choices you have made in life. How many people have sat back and pin pointed the day they put themselves out of the running to be President, or a doctor, or to marry that girl (or guy, as the case may be) that you had a crush on in high school?
But, that kind of thinking is can be counterproductive. The fact is that we each get one chance at life. Just as you can't eat every single flavor on a visit to Baskin Robbins, you simply can't be President and an astronaut and a pro-basketball player as well. The damage is most often done when people refuse to make any decent choice, because "they want to keep their options open." The fear of losing unrealistic opportunities does more to sabotage real opportunties than making decisions in life ever did.
Rather than asking ourselves, what opportunities have we foregone, we should be asking ourselves, what have I done with my life and what do I want to do now? Thinking about lost opportunties only leads to wistful angst. Appraising where you've been and asking where you want to go now, inspires action.