Compare: "Our TA was very unprepared for lecture. At 9 AM he simply asked the class if they had any questions, and didn't have a plan for discussion."
To: "He was always well prepared for sections but sometimes it would have worked out better if he would have gone with the flow more and not tried to stick to such a rigid game plan."
(One of these must be inaccurate, or else I was Dr. Jekyll in the afternoon and Mr. Hyde in the morning.)
"I got the impression that if I did not spend my whole evening reading the course materials than Matthew wouldn't be interested in my contributions, questions, concerns."
(The student resented being expected to read assignments, apparently.)
Elsewhere, I got the response I most hoped for: "He helped immensely in getting more out of the course packet readings. They always meant a lot more to me and made much more sense after the TA session."
Most flattering: "He really knew his stuff, but was one of the strangest people I have ever seen."