Failure is probably the most fatiguing experience a person ever has.
There is nothing more enervating than not succeeding being blocked, not moving ahead. It is a vicious circle. Failure breeds fatigue, and the fatigue makes it harder to get to work, which compounds the failure. In the former case, we keep putting off a task that we are under some compulsion to discharge. Either because it is too tedious or too difficult, we shirk it .