It just makes sense

I was in the car with my mother and I was moaning about two punctures that I'd had over Christmas and the problems of getting them fixed. The first was a nail in a tyre and the second a faulty valve in another tyre.
After a slight pause she said, "It's the garages."
"What do you mean?" I said.
"Garages drive around throwing nails in the street to get business," she said.
I had to really concentrate to keep the car on the road.
It's never boring with my mum around.