I think of ambition as I do money or technology—morally neutral but susceptible to manipulation. Gang leaders have ambition, sure. But so did Mother Teresa. Ambition isn’t inherently evil, but leaders must learn to channel it.
People with better self-control (or self-regulation, self-discipline, or willpower) are happier and healthier. They’re more altruistic; they have stronger relationships and more career success; they manage stress and conflict better; they live longer; they steer clear of bad habits.