During the Spring and Autumn Period (770-476 B.C.) there was an old farmer of Sung who led a very simple and frugal life. He lived in a thatched hut and wore shabby old clothes made of coarse cloth. To rest his bones he used to stretch out in front of his house and lie in the sunshine. Lying in the sun was so much fun, he told his neighbors one day, that he was going to tell the king about it before anyone else found out the secret. He was sure he would get a big reward.
But his neighbors stopped him. "There used to be a fellow who thought celery and duckweed was the greatest dish in the world so he recommended it to one of the local big shots. But when the big man tried it he didn't think it was all so hot and he wound up with a bellyache besides. Our friend ended up getting quite an earful and making himself look ridiculous in the process. Now you want to act as dumb as that celery and duckweed guy."
The expression "a country bumpkin offering sunshine" describes giving, with the best of intentions, something run of the mill and commonplace. It is now used as a polite phrase in offering gifts or opinions.
(Peter Eberly)