As I reviewed the Harvard Business School instructor I was very impressed. He was down to earth, was professional in his address to us, “seasoned instructors” and delivered an important message. Don't try and impress students allow them to express themselves and showcase their learning tools. If you come across as a "know it all" students will not appreciate you. They want to know that you have life experiences that make you normal but skilled, that you have made mistakes and relate to their current challenges. Don't teach to impress. Teach to engage!