My sister is raving mad

This evening over tea, my sister decided to talk about an old man living in a box. This is how the story went.

Once there was an old man, he didn't know how old he was so neither do I. Because he had been living in a box for nearly all of his life, he didn't know what other people looked like; he didn't even know what he looked like, because he just stared into nothing all day because the box was so dark that there was nothing else to do. One day his local radio station asked for people to phone in to say what exactly what they thought people are. This old man phoned in to the radio station and said "People, are very large beetles." Obviously everyone who heard laughed and the old man got very very cross.

So there it is, living proof that my sister is mad. After her amusing little tale she turned to me and asked if I thought she was mad, I replied "yes, I would even go so far as to say that I think you're bonkers."