Saki's nested short story "The Storyteller" is, like the term "nested" implies, a story within a story. The main character, a bachelor who has no choice but to share the cart alongside an aunt and her charges, is obviously annoyed by the fact that the aunt cannot take control of the children. While the aunt thinks that the bachelor is
a hard, unsympathetic man
the reality is that she is simply unable to monitor the children and, as a result, they are bored, annoying, and restless.
This is the inciting event: the children's current state motivates their aunt to tell them a story of righteous, if not overly moralistic undertones that, as children often do, they question to the core.
To counteract the ill-effects that the aunt's story is causing upon the children, the bachelor cuts into the conversation and tells his own story to the children: one in which the main character, an overly righteous little girl who succeeds at everything, gets eaten by an enormous wolf at the end after the sound of her many medals of merit gives her away.
Therefore, the motives of the aunt and the bachelor are the same because they both wish to quiet the children and to control them by whatever means are necessary. The bachelor, however, has yet another motive; to make the aunt look even more outdated and annoying than what she already is in the eyes of the children.