The crux of the parables is to bring forth a response, through a reference point that the audience will identify immediately.
This is like producing a smell in the 4D theatre that triggers a memory or emotion immediately.
The crux us the memory, but the smell is used to trigger it.
Eg intended memory : something smelly
For Singaporeans: smelly toufu
For China and USA: durian
Hence, our personal role in interpretating the parables in the bible, is to find the reference points which are extremely relevant for the audience, and recreate our own reference points, how would Jesus drive the message home for us.?
Eg mustard seed vs bamboo shoot.