Geez, I'd sure hate to have that teacher...
1. Super arrogant (teaches a practically useless magic but expects his student to study harder than everybody else, or else he's not worthy)
2. Bad at teaching (literally gives ZhangGong a book and tells him to memorize it, and ZhangGong's dad has to explain it to him)
3. Irresponsible (immediately after meeting ZhangGong goes off on a 3-month break)
I sure hope this training pays off for ZhangGong... lol