" We know that, when teaching students, only the utmost care and patience will ever work: we must never raise our voices, we have to use extraordinary tact, we must leave plenty of time for every lesson to sink in, and we need to ensure at least ten compliments for every one delicately inserted negative remark. Above all, we must remain calm.

And yet the best guarantee of calm in a teacher is a relative indifference to the success or failure of his or her lesson. The serene teacher naturally wants for things to go well, but if an obdurate pupil flunks, say, trigonometry, it is—at base—the pupil’s problem. Tempers remain in check because individual students do not have very much power over their teachers’ lives; they don’t control their integrity and are not the chief determinants of their sense of contentment. An ability not to care too much is a critical aspect of unruffled and successful pedagogy. "

― Alain de Botton