"Sick or else." I'm sure the bosses stick to that one as well when they're sick.
Where I work we have no sick days but they're actually pretty cool and don't hassle you if you call in sick....as long as it's not all the time.
It takes a LOT for me to call in, but I know my limits. Nothings worse than knowing you're coming down with something and you don't feel like going in....but you can't justify losing a days pay either. You know, it's that "it's trying to get me, but it hasn't kicked in all the way yet but it's coming" feeling.
If I have soupy poopies, I'm out. I work through everything else, but if I'm in danger of soiling myself, I'm goin home.