Where people differ from each other

A phrase the professor often says: "obviously obtained."

If you ask him to expand on "obviously obtained," he can fill four blackboards with calculations. He's not signaling how brilliant he is—calculating all four blackboards in his head in a second. He's simply not wasting everyone's time. Any work that can be done by just grinding it out gets summarized into those four characters: "obviously obtained." In the professor's eyes, that's your job. After class, whether you derive four blackboards or eight, that's on you.

Some students interpret "obviously obtained" as a hint that they need to work through it themselves later. Others don't get it, thinking it truly requires no effort, and end up failing the exam.

So how did the former group understand the professor? Through doing it themselves. They spent one sleepless night pushing through the derivation. The next day in class, eyes red from exhaustion, they heard "obviously obtained" again and thought to themselves: yeah right, nothing about this is obvious. That's when their perspective shifted. Through actual practice, they felt firsthand the labor hidden behind every "obviously obtained."

Students differ this way, and so do people in general. Some hear "obviously obtained" and take it at face value; others are the ones pulling all-nighters themselves.