I have a coworker who is oblivious to taking time off, she doesn't necessarily break any rules but the inconsiderate part of it is astounding. Her daughter is in her 20s but still she has to leave early/come in late/miss days because her daughter this or that ("needs to go to the dr", "has an appointment" - there isn't an ongoing health issue or anything, that'd be different, she's just over protective) - and often gets migraines (which I know are real things but they tend to fall on monday mornings, etc).

I think there are some general rules of respectfulness and not taking advantage that a lot of people don't understand/follow
Modified CG since Dec 2011