Those who can, do; those who can't, teach
Those who can, do. Those who can't, teach.
Those who are especially skilled in a certain field or area will be able to pursue a career, while those who are less skilled will end up teaching about it instead. A: "I know he always aspired to be a great novelist, but the last I heard he's still teaching middle school English." B: "Well, those who can, do; those who can't, teach."
Those who can, do; those who can't, teach.
Prov. People who are able to do something well can do that thing for a living, while people who are not able to do anything that well make a living by teaching. (Used to disparage teachers. From George Bernard Shaw's Man and Superman.) Bob: I'm so discouraged. My writing teacher told me my novel is hopeless. Jane: Don't listen to her, Bob. Remember: those who can, do; those who can't, teach.