Slack

There are some boys who are slack, unless pressed on; others again are impatient of control: some are amenable to fear, while others are paralyzed by it: in some cases the mid requires constant application to form it, in others this result is best obtained by rapid concentration. Give me the boy who is spurred on by praise, delighted by success and ready to weep over failure. Such a one must be encouraged by appeals to his ambition; rebuke will bite him to the quick; honor will be a spur, and there is no fear of his proving indolent.

Still, all our pupils will require some relaxation, not merely because there is nothing in this world that can stand the constant strain and even unthinking and inanimate objects are unable to maintain their strength unless given intervals of rest, but because study depends on the good will of the student, a quality that cannot be secured by compulsion. Consequently if restored and refreshed by a holiday they will bring greater energy to their learning and approach their work with greater spirit of a kind that will not submit to be driven.

Quintilian, Institutio Oratoria Book I iii 6-10