“Escalation of commitment is a major factor in preventable failures. Ironically, it can be fueled by one of the most celebrated engines of success: grit. Grit is the combination of passion and perseverance, and research shows that it can play an important role in motivating us to accomplish long-term goals. When it comes to rethinking, though, grit may have a dark side. Experiments show that gritty people are more likely to overplay their hands in roulette and more willing to stay the course in tasks at which they’re failing and success is impossible.”