"Pride goes before a fall." Knowing your weaknesses is a key business skill; honestly assessing to yourself the weaknesses in your position gives you the opportunity to protect yourself. It sounds obvious to say it, but the casualties keep piling up. It's been my experience that the most common symptom is getting too far ahead of yourself, looking too far past your current challenges, and so missing some key detail in the environment. I'm trying to keep my eye on the ball.