Imagine That: Forgetfulness

Imagine everyone forgetting everything. I don't mean all at once. I mean
little by little. Like a fog coming in from the sea, or a smell drifting
through the house. Everyone forgets, and they know they're forgetting, but
they can't stop it from happening! Horrible.
We were driving home when it started. The forgetting I mean. Dad was talking
about something and Mum was ignoring him. As usual. I was half asleep in the
back seat.
"Are we going somewhere, or coming back from somewhere?" said Mum.
"We're going home. I think?" said Dad.
"Don't be silly," I said, "We've just been to the Wilson's!"
"Oh yes, that's right." said Dad.
"Have we?" said Mum, "What did we do there?"
"We had a look at their garden, and walked round their house. It was as dumb
as!" I said.
"Don't use that expression, please," Mum warned.
"Dumb as."
"Do what your mother tells you!"
"Yes Dad."
Silence.
"Was it a nice garden?" asked Mum.
"Can't you remember?" laughed Dad.
"No" said Mum.
"Yes, it was a nice garden."
"Are you sure? I can't recall a bit of it. What sort of garden was it?"
"The usual. Trees, shrubs, a few roses. I was more interested in the house."
"What sort of house do they have?"
"Oh come on dear! You're having me on, aren't you?"
I sat up. Interested.
"How long have we known the Wilson's for?" asked Mum.
"About twenty years" said Dad, "You and Millicent went to school together."
"Did we?"
"Hey!" I said, "Why did you go past our gate!"
Dad slowed the car and stopped.
"We live around here somewhere," he said, "Its funny, but I can't quite
remember which house."
"Dad!" I said, falling back in a fit of laughter "Good one!"
But Dad wasn't laughing. Or smiling. He was really confused. He swung round
and started to drive back down the road, slowing down near the place I had
indicated.
"Here?" he asked.
"You should know," I said, "We've lived here for about nine years!"