I have quite a bit of ambition. It's useful and it feels good, and when ambition leads to achievement it gives me a good amount of life satisfaction.
That having been said, it's important to me to set my own ambitions and not have them shaped by societal expectations. Society says my career ambitions "should" take me into management, but I don't want to go into management. My ambition is to be a better engineer, because that is what is important to me, so that's the direction I take my career.
Ambition is half motivation and half thinking about the world in a goal-oriented way. Patterns of thought can be cultured and made into habit, good or bad, and ambition is no different.