Such a good question. I am a business owner and feel like I am making bad decisions when I am having a pois day. Then I beat myself up after the fact for my bad performance. So frustrating. My answer to you is this. I think its always best to go to work. There can be many reasons why someone is not at their best at work. i.e. colds, pain medication, emotional problems. Co-workers and management knows you can't always be at your best. But I understand your pain. I can barely think on pois days.