Fascinating post and video from TrueHoop's Henry Abbott. Abbott is getting coached by the instructors at the IMG Academy, who coach many of the top basketball talents coming out of high school.
During ballhandling drills, Abbott's coach instructs him to dribble the ball hard, at an uncomfortable speed, and Abbott notes that all the times he received praise, it was when he has turning the ball over.
His coach explained that to prepare someone for the speed, strength, and defense of an NBA player, he wants his students to get used to feeling uncomfortable and being pushed beyond their normal limits. If they can get used to that feeling, they won't panic when it occurs during a game situation.
There's a ton of advice you can draw from these principles. My personal conclusion is that it's important to practice in areas beyond one's personal comfort zone, so that you're ready when life presents you with the unexpected. Rather than freezing up or panicking, you'll be experienced in getting past the discomfort and still performing at a high level.