Ambition : An eager desire for social standing, fame, or power.
When ambition is led by greed of power and wealth, selfishness hatred and pride, it is destructive to both the pursuer and his fellow human beings. When it is lead by noble virtues of truth honesty, compassion and humanity it has the power to generate miracles and naturally mankind has benefited from them.
Ambition is not a weakness unless it is disproportioned to the capacity. Ambition is so powerful a passion, that however high we reach we are never satisfied and this very dissatisfaction if moulded and proportioned in a proper way, enables the pursuer to attain new heights and to have love and respect from his fellow beings.