I work until 7pm on Wednesday and Thursday, because Sunday is a short day. I need to make up 2hours each week and the extra hour for two days is what I chose.
Most evenings, the only Librarians left in our department are those who are working the late shift that evening.
Wednesday evening, "Mouth-All-Mighty" was at her desk after 6pm. I thought, she must be staying late because she won't be in tomorrow. Like clockwork, when I arrived on Thursday morning, she had called in sick.