But sometimes, the classrooms we describe bear little resemblance to the classrooms where we actually teach, and that gap serves no one.

Any honest discussion between teachers must begin with the understanding that each of us mingles the good with the bad. One student may experience the epiphany of a lifetime, while her neighbor drifts quietly off to sleep. In the classroom, it’s never pure gold or pure tin; we’re all muddled alloys.

I taught once alongside a first-year teacher, Lauren, who didn’t grasp this. As a result, she compared herself unfavorably to everyone else. Every Friday, when we adjourned to the bar down the street, she’d decry her own flaws, meticulously documenting her mistakes for us, castigating herself to no end. The kids liked her. The teachers liked her. From what I’d seen, she taught as well as any first-year could. But she saw her own shortcomings too vividly and couldn’t help reporting them to anyone who’d listen.

She was fired three months into the year. You talk enough dirt about yourself and people will start to believe it.

Omission is the nature of storytelling; describing a complex space—like a classroom—requires a certain amount of simplification. Most of us prefer to leave out the failures, the mishaps, the wrong turns. Some, perhaps as a defensive posture, do the opposite: Instead of overlooking their flaws and miscues, they dwell on them, as Lauren did. The result is that two classes, equally well taught, may come across like wine and vinegar, depending on how their stories are told.

Take the first year I taught psychology. I taught one section; my colleague Erin taught the other.

When I talked to Erin that semester, she’d glow about her class. Kids often approached her in the afternoons to follow up on questions, and to thank her for teaching their favorite course. Her students kept illustrated vocab journals totaling hundreds of words. They drew posters of neurons, crafted behaviorist training regimes, and designed imaginative “sixth senses” for the human body. Erin’s mentor teacher visited monthly and dubbed it an “amazing class” with “incredible teaching.”

Catch me in an honest mood, and I’ll admit that I bombed the semester. I lectured every day from text-filled overhead slides. Several of my strongest students told me that they hated the class and begged for alternative work. I wasted three weeks on a narrow, confining research assignment, demanding heavy work with little payoff. One student openly plagiarized another. I wound up failing several students who, in hindsight, I should have passed. Yet I know that this apparent train wreck of a class was, in truth, no worse than Erin’s.

That’s because I made Erin up. The two classes described above were the same class: mine. Each description is true, and neither, of course, is wholly honest.