At Amazon, workers are encouraged to tear apart one another’s ideas in meetings, toil long and late (emails arrive past midnight, followed by text messages asking why they were not answered), and held to standards that the company boasts are “unreasonably high.” The internal phone directory instructs colleagues on how to send secret feedback to one another’s bosses. Employees say it is frequently used to sabotage others. (The tool offers sample texts, including this: “I felt concerned about his inflexibility and openly complaining about minor tasks.”) Many of the newcomers filing in on Mondays may not be there in a few years. The company’s winners dream up innovations that they roll out to a quarter-billion customers and accrue small fortunes in soaring stock. Losers leave or are fired in annual cullings of the staff — “purposeful Darwinism,” one former Amazon human resources director said. Some workers who suffered from cancer, miscarriages and other personal crises said they had been evaluated unfairly or edged out rather than given time to recover.