I have written often about the importance of working hard.
But I also said, "he who takes rest is greater than he that can take cities."
At the end of a good productive day, it is just as important to get some good rest. In fact, not getting enough rest can be dangerous according to a study by the Journal of Occupational and Environmental Medicine. It reports that getting less than 5 hours of sleep a night, two or more times per week, can double your chances of having a heart attack.
So when the day is done, and you've contributed your best to getting the mail delivered -- go home and get some adequate rest. It's the best thing you can do for yourself and the Postal Service!