My favorite teachers and professors have been those who were passionate about the subject matter, but kept an open mind when it came to people's learning styles. I actually enjoyed the ones who challenged me intellectually, but my favorites always had an open door policy and would be pretty accessible when it came to asking for help.
I remember being terrified my first two years of college when it came to participating in class discussions, but after getting used to it, I found that the professors who incorporated them during part of the lecture were the ones who cared the most about how well their students retained the material. Looking back, I feel that I learned the most when sharing ideas out loud like that because it helped to clear up any confusion.