I think I will just share two comments with you here.
"Started class early - unacceptable as many students have class before. She didn['t] answer any questions. RUDE! ..."
"I really enjoyed learning from Dr. Yu. I want to say I appreciate her + her knowledge very much and apologize for some of the other students in the class. Thank you! I learned a lot."
ps. I feel sorry that some students felt that way about me. I could not imagine how they must have suffered...