One of the early lessons we all learn is we will not always come out on top. Your team is not always going to win. Your best efforts are not always good enough to earn the first place trophy. Your hard work is not always going to result in a promotion. But that shouldn't deter each of us from giving our absolute best effort.
I am extremely competitive when it comes to succeeding and use other people's success to drive me to do better. I have determined to be satisfied with failing as long as I know I gave my best effort. I'm not sure I can ask more of myself than that. The question I ask myself is 'did you give your all?' and if the answer is 'yes' then I am satisfied. If my answer is 'no' then I return to the drawing board and figure out how I could have performed better.
Ultimately the only person who will know if you gave your all is you. Identify your weaknesses, improve upon your effort and move forward. That's what I try to do; that's all I can do.