Don’t drink during work hours.

Your work arrangement may allow for flexible working hours. If you’re burning the midnight oil by yourself, it’s probably harmless to enjoy an alcoholic beverage as a special treat. As a rule, though, don’t drink and work. It may impair your ability to do an adequate job in the first place. It can also lead to all kinds of problems as you interact with others, synchronously or asynchronously. If you feel like you’ve had quite a day and need a drink to unwind, by all means, do so. Clock out first and then enjoy.