Hello. You forgot to present the comic to which the question refers. The comic is in the attached image:
Answer and Explanation:
The public knows that the falling of the leaves is a natural process of nature, but the character believes that the leaf fell due to this dissatisfaction with the place where he lives, just like him. In this case, the character leaves disappointed because the leaf fell from the tree and this generates humor in the comic, mainly because he reflects on life while observing a dead leaf.