Did She Really Not Know?
This one appears to be an accident. After telling her about her excellent grade in chemistry class, we get the impression that this mother was deliberately joking around with her daughter. Of course, it’s conceivable that she truly believed “WTF” meant “Well That’s Fantastic,” but we don’t think this is the case.
That would imply she was informed, implying that a significant portion of society is employing this phrase incorrectly. But who knows? Perhaps there is…