Forget for a moment about the moral dimension of Lance Armstrong's behavior: the lying, the cheating, the bullying. I don't understand why he would risk so much for athletic glory. Would I like to win the Tour de France? Of course I would. It's the pinnacle of athletic achievement. It's the hardest event in the hardest sport. The question is what I would be willing to do to achieve it. I would never consider risking my life or health. This isn't to say that I'm risk-averse. If I were, I wouldn't ride a bike at all, because it's dangerous. (Recall my shattered collarbone in June 2012.) But these risks are inherent in the sport. Taking drugs is not inherent in the sport.
I'd rather ride clean and lose the race (even finish last) than cheat and win. Evidently, Armstrong made the opposite choice. He was willing to do whatever it took to win, including risking his life and health. I don't understand that mentality, and probably never will.