Managers can be dense. But the manager in this story makes most managers seem like aerographite in comparison. (One of the world's least-dense materials, duh.)
Recently, a manager at a customer service center wrote into the advice site Ask a Manager. This customer service manager wanted to know the right way to approach an ex-employee who quit on the spot because the manager wouldn't give the employee two hours off to go to her own graduation (the employee was taking night classes part-time). The manager explained:
I told this team member that she could not start two hours late and that she would have to skip the ceremony. An hour later, she handed me her work ID and a list of all the times she had worked late/come in early/worked overtime for each and every one of her coworkers. Then she quit on the spot.