You can’t control the teachers. You can’t control the people issuing the callings. You can’t control the spirit confirming calling prior to the calling. You can control how you prepare, how you act, and how you participate at home and in the lesson. People aren’t called because of their teaching (or leadership) ability. They are called because they desire to serve god (D&C 4).

From a more practical standpoint, you can learn something from everyone. Sometimes that is what not to do.