Results of working hard

Have you ever worked hard for something, and the results were not what you expected? Some people say that if you work hard for it, you will eventually get it. Sometimes that's not the case. There are times that I work hard for things and I still end up doing bad. Really pisses me off.lol Its because there are people out there that barely try and still do better then you. But it only happens sometimes. I still believe that if you work hard you will succeed. Its just those random times that you do work hard and still fail that really annoys me.