What's the use of leaving a note for an absent poem when writing a pine tree in the sky? How does the whole poem express the poet's feelings

The poet used the technique of asking and answering questions to describe the anxiety of not finding a place. White clouds are nobler than hermits, and pine trees are used to describe hermits' character. The more I admire you when I didn't meet you when I was writing. The writing is popular and beautiful, complicated and concise, and the feelings are profound and unpretentious.

The hermit in the poem collects medicine for a living and helps the living. He is a real hermit. So Jia Dao has admiration for him. Only in this way, admiration and the satisfaction of failure highlight their disappointed feelings.