Dedication

All my life I've been having this problem. I must be honest with myself and admit that I'm lazy as hell. My level of dedication for my goals is really low. I can get some things that I want but not ALL of them. I'm not dedicated enough to my own cause. Everything I have accomplished until now was by doing as little as possible with the least effort as possible. I feel kinda like Homer Simpson as I write this last sentence.

I need to be more dedicated, to my job and my goals. I know that I have great potential but I don't exploit it. I have mood swings of ups and downs and the downs seem to make me stop pushing to reach my goals. I will be motivated to the point where I nearly reach it, but at the end, I deliberately destroy everything I've worked hard for and give up. Am I afraid of success? Is there a part of me that does not believe that I deserve the best?