In school, whether in college, high school, or below, we all may have a class we're eager to get out of for some reason. (It's boring, the teacher is terrible, lunch is next period, etc.). So when we see time counting down till the end of class, some of us get our stuff ready to scramble to the next class. If the teacher is a Clock however, that's not happening any time soon. These teachers insist on everyone having their stuff out until the bell actually rings and they hate when people start to pack up five or so minutes before class ends. Their catchphrase just a minute before the bell rings is "Don't pack up yet. Class isn't over." These teachers scold their class for not focusing in class until the very last second and may keep their class sitting in their seats for an extra minute or two after class ends just to make sure there's no repeat of said behavior.