A direct way to exhaust yourself:

• You start your day with a general, vague sense of your priorities.
• To prevent yourself from making progress, you don't write your tasks down anywhere. Then you can remember a particular task while busy with another, briefly panic, and doing it all over a few minutes later.
• You don't make a list or schedule a time for any task. This could make the list of tasks feel manageable, and might also lead you to start one task at a time. You want to feel vaguely overwhelmed at all times.

To help you get nothing done while feeling exhausted, don't take breaks during unplanned work. Keep struggling.

Do tasks that don't directly accomplish anything. Email and Slack are great for this because neither are directly productive or relaxing. Check Twitter or read the news to get a general sense of anger or anxiety.

One study suggests that working out improves both productivity and satisfaction.

Staying in your chair and moving as little as possible is a sure way to feel exhausted at the end of the day.