There may be 2 cases further on:

1. The event is recurring- In such a case, where you get a second chance, you should build your first. Hard. One's best efforts are also dependent upon time given. A punch from 18 inces is way much stronger than a punch from 1 inch. Try hard the next time. Turn your tears of disappointment to those of vengeance. Bounce back-1 month, 3 month or 3 years. For this will be stupendous this time. ;)
2. 
   

2. The event is non-recurring- In this case, where this was your first-and-last or first-or-last chance, and you failed, when someone tells you that it's ok, you are probably going to punch him in the nose. Yes, it isn't ok if this was your last chance, but it shouldn't be your last chance of your life I guess. Change the direction of your efforts. Maybe you spent your whole efforts pushing on an immovable wall. Try to push a sandbag, rather. You will succeed, my friend. Just need to put the right efforts for the right duration in the right direction.