The Chinese expression "the frog in the well", is a metaphor for a person who has little experience or knowledge yet exudes self-importance.
The metaphor describes a frog who lived happily in an unused well, contentedly splashing in the water and wondering aloud if anyone could be as well satisfied as he.
One day, a sea-turtle passing outside the well heard the frog and said to him, "Brother, have you ever seen the sea? It is so vast that once there was a seven-year drought, yet its waters did not recede. It is only in the ocean that I'm truly content."
At these words, the frog was deeply ashamed.
(Gerald Hatherly)