Call me delusional if you want to, but I like to define my personal concept of success as something that is very very hard, Even nigh impossible, to attain. This way, I would never be satisfied with myself, and I would always have a reason to push myself even more.
In other words, I disagree with the notion that ensuring your own survival without sacrificing your pleasures is success. I would only consider myself successful if, on my deathbed , I can look back at my life and say that I achieved everything that I could achieve,and that I could not achieve what I did not.