The goose that laid the golden eggs

I read The goose that laid the golden eggs, Usborne first reading, level 3 book.
A husband and wife had what they wanted and lived happily.
One day a goose laid a golden egg.
They sold one and they found that it was very precious thing.
Therefore, they decided to get more gold from the goose...
What will they do next?

I think that this story is very sad story.
And it is bad that to get good things too much.
Although they lived happily so far, they get too much luxury.

They are too greedy.
I found that the ordinary life is the most precious time.