I follow a blog called Simply GTD. There was a new post there called @BrainToast. Read through the post and see if you see what I saw. Here's the comment I posted.
Why wait around for the boss? If your brain is fried, why not leave for the day? Is not the results you produce what's important? Perhaps you will have the great insight your company has been waiting for at 3 am Saturday morning. Do you wait until 9 am next Monday to do something about it?
I don't think that appearances are what's important. I know I wouldn't hang around on a Friday afternoon doing low-value tasks for the sake of impressing my boss with my "dedication."
What do you think?