These are "words that do their job in the most sarcastic, sullen, passive-aggressive way possible, and they totally get away with it!"
[Hat tip: Amy de Buitliér]
[Update -- Laura Dickerson writes:
The series of children's books featuring Amelia Bedelia are based on the idea that she takes everything literally. In the first book of the series, the woman employee her as a house cleaner has to remember to say things like "un-dust" the furniture, having learned the hard way that saying "dust the furniture" will prompt AB to put dusting powder all over it.
But Neal Whitman, who is really Literal-Minded, begs to differ.]
[This concept was discussed here, with many examples, using the term "contronym". Or perhaps I should say, a family of similar concepts...]
Posted by Mark Liberman at November 3, 2007 12:36 AM