When you just can't be bothered to do your actual job, but want to make sure your coworkers are kept on their toes.
This is where the art of Sabotage by Design comes in - making the workplace more interesting, one poorly designed interface at a time.
By purposefully creating confusing and frustrating interfaces, you can make sure that everyone is kept on their toes.
And if that's not enough, you can always accidentally delete important data just for good measure.