Ball State University economist Steve Horwitz posted to YouTube an excellent clarification/gentle rant about the difference between having a monopoly and being big. Though aimed at one his undergraduate classes in which many students were making repeated slips, it is a good reminder for just about everyone. This is what good teaching looks like.
The seven-minute video is here. It is even shorter than that if, as I often do, you play the video at 1.5x speed or so.