'Just Do It' is the tag line of one of the famous companies. Whoever thought out that line, has done it well because that is all there is to life in any aspect.
Just go ahead and Do it.. whatever it is. You have a chance, you may have a choice, but you just do it. And the response of the doing does not always have to be visibly, immediately, in your favor. You did it because you wanted to do it. Simple. If you are doing something because someone else asked you to, that someone else wont be there to take the hit of it, if any, later.
You are solely responsible for what you do.