Leonie at Living without School was describing why she is an unschooler and certainly the above is one reason why I consider unschooling, to use Julie's terminology, to be "the holy grail of home education methodologies".
"The fourth fundamental disposition concerns the sense of a job well done, for next to the attitude toward existence there is nothing more basic in man's psychic life than the attitude toward work. I do not mean by this the habit of being hard working. I am aware that laziness, as well as pride, is natural to us. Moreover laziness in children is often not real laziness but only an absorption of the mind with the workings of vegetative growth or psychophysical hardships.
I am speaking of something deeper and more human, a respect for the job to be done, a failing of faithfulness and responsibility regarding it. A lazy man, a poet if you will, may display, when he happens to work, the most passionate attachment to the inner requirements of his work. I am convinced that when this fundamental disposition, which is the first natural move towards self-discipline, this probity in regard to work is marred, an essential basis of human morality is lacking. "
This probity of attitude towards the "inner requirements" of work is one of the most important things to be nurtured in the homeschool. I have seen people say that children can not learn to value work unless they are forced to do it, but I think it's almost the opposite.
I think that unless the children learn to work hard by their own decision, because of their interior relationship to the requirements of the work itself, they will never have the probity of attitude Maritain describes.
Training in habits and "requirements" can sometimes be of aid in this, but can't stand in as a replacement.