I heard a little story, let me share it with you:

Both are good beans, but why can red beans represent longing, while green beans can only be paired with turtles?

Later I found out that red beans are bitter with a little poison, while green beans clear heat and detoxify, and the more you cook red beans, the more bitter they become, while the more you stew turtles, the more nourishing they are. Therefore, longing is bitter, turtles are very nourishing; longing is worthless, but turtles cost eighty per pound.

In youth, one does not know the bitterness of longing, but in middle age, one understands the nourishment of turtles.