“One of the big reasons I quit was sort of intangible,” Ingersoll says. “But it’s very real: It’s just a lack of respect,” he says. “Teachers in schools do not call the shots. They have very little say. They’re told what to do; it’s a very disempowered line of work.”

Other teachers—especially the younger ones—are also leaving the classroom for seemingly nebulous reasons. I spoke with nearly a dozen public and private school teachers and former teachers around the country. (I used pseudonyms for the teachers throughout this piece so that they could speak freely.) Many of them cited “personal reasons,” ranging from individual stress levels to work-life balance struggles.

“We are held up to a really high standard for everything,” says Emma, a 26-year-old former teacher at a public school in Kansas who now works for a music education non-profit. “It stems from this sense that teachers aren’t real people, and the only thing that came close to [making me stay] was the kids.”

In my interviews with teachers, the same issues continued to surface. In theory, the classroom hours aren’t bad and the summers are free. But, many young teachers soon realize they must do overwhelming amounts of after-hours work. They pour out emotional energy into their work, which breeds quick exhaustion. And they experience the frustrating uphill battle that comes along with teaching—particularly in low-performing schools.

“What people are asked to do is only the kind of thing that somebody can do for two or three years; you couldn’t sustain that level of intensity throughout a career,” said Thomas Smith, a professor at Vanderbilt University’s education school. He was referring specifically to charter schools, but his sentiment is one that resonates with many beginning teachers in challenging schools. “[It’s] the same way that people might think of investment banking. It’s something that people do for a few years out of college, but if you want to have a family, or you want to have some leisure time, you know, how do you sustain that?”

Joseph is a former Advanced Placement U.S. History teacher who loved his first years in the classroom; after a couple of years, though, he came to a saddening realization about the future of his career.

“I realized that most older men I taught with eventually felt pressured to advance into higher-level administration as their careers progressed in order to better support their family,” he said. “What many of them working in high-need schools told me, however, was that being successful at school directly conflicted with being successful husbands and fathers. While this is certainly true of any occupation, most occupations don't leave your children asking you, ‘Why do you go to more basketball games of the kids at school than mine?’"

Pay is also an issue that came up in my interviews. A starting teacher salary in the U.S. is $35,672.