Took me awhile to learn this, but... If you want/need a day off or two, don't ask, just call in. Once again, naive old me tried to "do things the right way" and ask for a day off to visit a friend in the hospital. My request was denied of course. Show up to work on the day I wanted off and of course, I wind up staying late again to cover for everybody else that called in. Never asking again.