My first year of a 2 year course our teacher had only taught us 2 theory topics of 6 and hadn't begun to teach us the other 2/3 of the course which was programming. The only reason he took so long was because he wanted everyone to understand the topic before he moved on which meant waiting for the people who shouldn't of been allowed to take the subject because they never paid attention and showed no interest in the subject. But he refused to move on without them.

To drag those 2 topics out more one of them was algorithms. At the time he had sprained his wrist shadow boxing and instead of preparing them before hand to give us some help he would type them out while we sat and watched wasting half the lesson. Then a month or so into our second year he left leaving the other teachers to make up for everything he failed to cover with us.