The second-to-last question on my MATH 280 students' final exam, designed, as was the last question, to get the students to perform a bit of reflective self-analysis, reads:
Go back over all of the proofs you've written in our class this semester, and select the single proof which you believe to be the clearest, the most complete, and most correct...that is to say, the BEST...of all of the proofs you've written this term. You may consider proofs in homework assignments, exams, or textbook chapters. Write a couple of paragraphs explaining why you selected the proof you have. Why is it that this proof represents the best you've got?
I'm currently grading this question, and I'm gratified to find that a very large number of the students are selecting the proofs that they are because those particular proofs were the ones which helped instill confidence in their abilities to do math, and to complete proofs. To me this fact underscores the importance of confidence and other affective aspects of learning. Kudos to my colleagues who work as hard at developing students' affective engagement as they do at ensuring cognitive mastery!