It may not be your seemingly endless to-do list that leaves you exhausted at the end of the workday.
In fact, Business Insider reports it may be because you're tired of faking your emotions!
Scientists call it "surface acting," or hiding your real feelings in an effort to please coworkers or clients.
The pattern is linked both to health problems and to worsening performance at work.
Penn State professor Alicia Grandey sees a link between surface acting and mistakes on the job.