When I was an undergrad, I had to take a calculus class. It was not difficult for me, but I can't forget what the professor said in class that I thought was amazing and inspired me in other courses. He mentioned in class that all he wanted to do was be a mathematician. So he went to college and enrolled in a trig class, I believe, and failed. He thought he was awful at math. Then he decided to go back to Algebra I. He said that he needed to get the fundamentals, and gain confidence, before tackling more complex problems. So that's what he did. He took longer to graduate, but he said that had he not gone back, and practiced the "easy" stuff first, he would have abandoned math forever. So he illustrated both the importance of practice and feedback in learning, as well as informing the students that even a math professor can struggle with math, thereby creating a much more inviting classroom.