Which lines demonstrate the generation gap in the short story "The Lumber Room" by Saki?

There are a number of lines in the short story “The Lumber Room” by Saki that demonstrate the gap between the generations. The story illustrates the difference in reasoning skills between the generations, and it is not always the older person who is wiser and more intellectual. In fact, the child, Nicholas, is able to outsmart the adults, especially the aunt, who is the primary disciplinarian in the story.
When Nicholas attempts to tell the adults there is a frog in his breakfast, they admonish him. They tell him not to be silly.

Older and wiser and better people had told him that there could not possibly be a frog in his bread-and-milk and that he was not to talk nonsense; he continued, nevertheless, to talk what seemed the veriest nonsense, and described with much detail the coloration and markings of the alleged frog.

Of course, by Nicholas' own doing there is a frog in his bowl, and again the generation gap is expressed.

The sin of taking a frog from the garden and putting it into a bowl of wholesome bread-and-milk was enlarged on at great length, but the fact that stood out clearest in the whole affair, as it presented itself to the mind of Nicholas, was that the older, wiser, and better people had been proved to be profoundly in error in matters about which they had expressed the utmost assurance.

After a long afternoon of mentally sparring with the aunt, she ends up trapped in the water tank in the forbidden gooseberry garden. Again, Nicholas manages to outsmart her with his words. She finds herself stuck in the tank while Nicholas walks away knowing he reached his limits.

There was an unusual sense of luxury in being able to talk to an aunt as though one was talking to the Evil One, but Nicholas knew, with childish discernment that such luxuries were not to be over-indulged in.