If you believe that your life is made of the choices you make, then the choices you make gain a paramount importance. Now in this framework, life is pretty simple. At each stage, you evaluate the choices you have - and choose one. If there is no choice, then you pretty much can't do anything - so there is nothing to feel bad about.

Though there are a few nuances here is:

  1. Are you evaluating ALL the choices you have? Many a times we severely limit the choices we consider by considering how difficult they would be or how improbable. However difficult or improbable, they are still a choice.
  2. If you make a choice, and it doesn't work out - can you do something to achieve the same goal? The funny thing is that, many times the choices are time dependent - and you can't redo the same choice. You can't rewind the proverbial clock. And that brings the idea of regret.

You have made you choice which you can't undo, and now you petty yourself. Mostly what I have seen is that most material choices - like those about career, money, success, etc. can be made again.

e.g. If you made a choice of become a trader, even though at heart you always liked Physics more, you always have a choice to start doing Physics if you realise that money doesn't excite you. It may be a difficult choice, but you do have a choice nevertheless.

Though in certain matters it doesn't work. If you wanted to propose a girl when you are young, you can't do that when she is 40 and married with two kids. You can't rewind the clock. And, this is what leads to regret.

An interesting, and I would say "effective" framework to make decisions is what some people have referred as "Regret Minimization" framework. Make those choices which you think you will have minimum regrets, if it doesn't work out. Jeff Bezos is famously known to use this framework.  Sounds like one of the better frameworks to make decisions to me!