The rut has grown so deep, and they have sunken in so far that they cannot look over the edge.
It is true that it is easier to do good hard work in the lines to which one has been accustomed than to do easy work which is strange.

Nerves will go on in old accustomed habits--even habits of tiresome strain--more easily than they will be changed into new habits of working without strain.
The mind, too, gets saturated with a sense of fatigue until the fatigue seems normal, and to feel well rested would--at first--seem abnormal.
This being a fact, it is a logical result that an habitually tired and strained mind will indignantly refuse the idea that it can do more work and do it better without the strain.
There is a sharp corner to be turned to learn to work without strain, when one has had the habit of working with it.

After the corner is turned, it requires steady, careful study to understand the new normal habit of working restfully, and to get the new habit established.
When once it is established, this normal habit of work develops its own requirements, and the working without strain becomes to us an essential part of the work itself.
For taken as a whole, more work is done and the work is done better when we avoid strain than when we do not.

What is required to find this out is common sense and strength of character.
Character grows with practice; it builds and builds on itself when once it has a fair start, and a very little intelligence is needed if once the will is used to direct the body and mind in the lines of common sense.
Intelligence grows, too, as we use it.

Everything good in the soul grows with use; everything bad, destroys.
Let us make a distinction to begin with between "rest while you work" and "working restfully." "Rest while you work" might imply laziness.