A classic scenario between mother and child. Either through the child's one-off expression of preference, or because the mother is simply mistaken, the mother gets it into her head that her son likes cheese sandwiches.
She will then give her son cheese sandwiches until he finishes his GCSEs. The son will at first eat them, because - after all - he likes cheese sandwiches. Soon, they will be left, rotting, in long-forgotten bag pockets and hedges on the way to school. After five years, the boy might even have to find new ways to walk to school, to avoid over-saturating certain roads with cheese fucking sandwiches.
I did bring this up with my mother in adult life, and she asked me why I didn't say anything at the time. But... you can't, can you?
NOTE : Use this effect to your advantage with less-visited and possibly housebound relatives, who will fill their home with your favourite thing, and you can go around there whenever you feel like it.