....is not "42" but rather "Self-Awareness" - this article in Forbes is a neat reminder of both the critical importance of self-awareness as a route to effectiveness and how 360 degree feedback is one of the most effective means of developing such self-awareness.
Naturally I am biased, but I do find myself vigorously nodding in agreement - there is a wonderful simplicity and affirming belief too at the heart of this; trust people to know what to do once they have the information to hand, once you have explored their 360 degree feedback report with them in the debrief.
If you can raise their self-awareness and bring what's often in their peripheral vision into view, they will often make 'better' choices next time around.