Ronald Reagan famously quipped that "it's true hard work never killed anybody, but I figure, why take the chance?"
Beyond a certain level, extra effort seems to be self-defeating.
Studies suggest that, after 50 hours a week, employee productivity falls sharply.
But that doesn't stop some managers from demanding that workers stay chained to their desk for long periods.
At the blood-testing firm Theranos, Sunny Balwani, then boyfriend of the founder, Elizabeth Holmes,
had an obsession with employee hours, and would tour the engineering department at 7.30pm to check people were at their desks.
All those hours were wasted when the company eventually collapsed (prosecutors have charged Ms Holmes and Mr Balwani with fraud).
Jack Ma, the founder of Alibaba, a Chinese e-commerce group, recently praised the "996" model,
where employees work from 9am to 9pm, six days a week, as a "huge blessing".
即员工上班时间为早上9点到晚上9点，一周工作6天— 是一种巨大的福气 。
To be fair, Mr Ma said employers should not mandate such hours. Still, presenteeism is the curse of the modern office worker.
公平地说，马云称雇主不应强制“996” 。然而出勤是现代上班族的诅咒 。
There will be days when you do not have much to do,
perhaps because you are waiting for someone else in a different department, or a different company, to respond to a request.
As the clock ticks past 5pm, there may be no purpose in staying at your desk.
But you can see your boss hard at work and, more important, they can see you. So you make an effort to look busy.
但你可以看到老板还在刻苦工作，更重要的是，他们也能看见你 。所以你努力让自己看起来很忙 。
Some of this may be a self-perpetuating cycle. If bosses do not like to go home before their underlings,
and underlings fear leaving before their bosses, everyone is trapped.
Staff may feel that they will not get a pay rise, or a promotion, if they are not seen to be putting in maximum effort.
This is easily confused with long hours.
Managers, who are often no good at judging employees' performance, use time in the office as a proxy.
The consequence is often wasted effort. To adjust the old joke about the Soviet Union:
"We pretend to work and managers pretend to believe us."
Rather than work hard, you toil to make bosses think that you are.
Leaving a jacket on your office chair, walking around purposefully with a notebook or clipboard
and sending out emails at odd hours are three of the best-known tricks.
'He'll have to go on a diet,' Ballard quipped
She would try to forget her obsession with Christopher...
His business empire collapsed under a massive burden of debt.
Her promotion to Sales Manager took everyone by surprise.