My opinion is that he who knows how to draw well and merely does a foot
or a hand or a neck, can paint everything created in the world; and yet
there are painters who paint everything there is in the world so
impatiently and so much without worth that it would be better not to do
it at all. One recognises the knowledge of a great man in the fear with
which he does a thing the more he understands it; and, on the contrary,
the ignorance of others in the foolhardy daring with which they fill
pictures with what they know nothing about. There may be an excellent
master who has never painted more than a single figure, and without
painting anything more deserves more renown and honour than those who
have painted a thousand pictures: he knows better how to do what he has
not done than the others know what they do.
_Michael Angelo._