Excellent question.
Ironically, I think that as I've gotten more successful, my ambition has waned. The reason is that, I made the mistake is seeking happiness in financial and career success. I put my all into the last years of college (before that I was a total fvck-up) and law school, and essentially gave my last few years of life to the goal of achieving a six figure salary.
I know have that, and you know what? I'm no happier. Of course, I abstractly knew that "money couldn't buy happiness", but like with most things in my life, I had to learn by experience, thinking somehow that conventional wisdom didn't ever apply to me, or at the least, that whoever said such a phrase was merely spouting "sour grapes". I'll tell you, its incredibly wierd to have a paycheck that I've dreamed of for so long, to be able to buy expensive and fancy things - although this is all relative since fancy and expensive to a regular Joe like me may be normal to some of you silver spooners - and I'm still with the same, somewhat empty feeling, but now with designer clothes, a nice watch, and lots of electronic gadgets to try and distract me from it.
So, the moral of the story is - make sure that you are ambitious for the right reasons, if there is such a thing. Seek to rise up the ladder to better your financial position, and gain financial independence, but KNOW that that is all that will happen. You won't become happier, and although hotter girls now hit on you, its all the more sad to realize that they just see you as a source of income, and are the exact kind of shallow, materialistic, self-torturing whores that remind you empty this whole money thing is.