Back in the day, I used to try to give a thorough lecture on every topic I taught: I did at least three examples (a medium-difficulty problem first, then a simple problem to reinforce the concept, and then a more challenging problem), making sure to incorporate every conceivable 'hiccup' the students might stumble over in completing their book-work.
After years of doing this, I realized that there was always very little time left during the class for students to actually do the work, particular