Often, the teacher will give good students a difficult time, pushing them 
to the limit (and perhaps beyond), for the purpose of testing both their 
character and technique. The teacher has to see whether they are strong enough 
and skilled enough to bear the strain. Although the demands may seem 
unreasonable at the time, students must not withdraw, lose faith and retreat. 
Only through trust and perseverance can one's character and spirit grow 
stronger.
(Adam Hsu)
(Adam Hsu)