Even if you care about nothing whatsoever except your job (which probably isn't - and certainly shouldn't be - the case) there is an optimal level of effort that delivers peak sustainable output, and for tasks with a significant intellectual component, the available data says that optimal level is about thirty or forty hours a week. Beyond that, sure, you'll get more done in the first week, but chronic fatigue will quickly build up, reducing your effectiveness to the point where you're actually getting less done than you would have in a thirty-hour week.
Let's see some of that research. "A Grand Gender Convergence: Its Last Chapter" Goldin, NBER working paper suggests that there are superlinear returns to hours worked for differentiated labour. Where workers are basically substitutable pay has an almos 1:1 relationship with hours worked. Where people can have unique knowledge and relationships and combinations of same working more hours makes your total output greater and makes you less substitutable, which makes your bargaining position better, if you're an employee.
Let's see some of that research. "A Grand Gender Convergence: Its Last Chapter" Goldin, NBER working paper suggests that there are superlinear returns to hours worked for differentiated labour. Where workers are basically substitutable pay has an almos 1:1 relationship with hours worked. Where people can have unique knowledge and relationships and combinations of same working more hours makes your total output greater and makes you less substitutable, which makes your bargaining position better, if you're an employee.