Reginald by Hector Hugh Munro

There was once (said Reginald) a woman who told the truth. Not all at once, of course, but the habit grew upon her gradually, like lichen on an apparently healthy tree. She had no children -- otherwise it might have been different. It began with little things, for no particular reason except that her life was a rather empty one, and it is so easy to slip into the habit of telling the truth in little matters. And then it became difficult to draw the line at more important things, until at last she took to telling the truth about her age; she said she was forty-two and five months -- by that time, you see, she was veracious even to months. It may have been pleasing to the angels, but her elder sister was not gratified. On the Woman's birthday, instead of the opera-tickets which she had hoped for, her sister gave her a view of Jerusalem from the Mount of Olives, which is not quite the same thing.

The revenge of an elder sister may be long in coming, but, like a South-Eastern express, it arrives in its own good time.