Found this from an online LDS site today:
Many individuals today make the false assumption that failure is the worst possible outcome. Contrary to popular belief, it is not failure that is the worst possible outcome but rather mediocrity.
Failing is definitely no fun but at least it allows you to move forward in a new direction or start afresh. Mediocrity on the other hand gives the illusion that you are accomplishing something when in reality you are merely moving from side to side. It wastes your resources, energy and most importantly, it wastes your time. Failure lets you move on whereas mediocrity stalls you and keeps you from reaching your potential.