Most school teachers I know are allowed up to 3 or 4 "personal days" per year. That way if their kid is sick, or they have something going on with the family, they can take off without "abusing the sick policy".
I am not sure if the sick section is TA'd or not (I should look, I guess), but it would be nice to be able to use sick leave for "personal leave" for up to, say, 3 or 4 days per year.
Then, for example, if you wanted to fly a private aircraft in an airshow, you could call in for a "personal day", and you wouldn't have to worry about any management guys hiding in the bushes with a video camera, waiting to bust you. Of course, that scenario would never happen at FedEx, would it?