what does Hamlet learn about the importance of wordly deeds after death when he looks at the skull?

The gravedigger says that this is the skull of Yorick, the old king’s jester. Hamlet is amazed – he knew Yorick and loved him as a child. He takes up the skull and speaks about Yorick, a topic that leads him to consider the nature of mortality more generally. Hamlet wonders how everybody, no matter how great or small, return to the dirt of the earth. Hamlet ponders on the briefness of life and the inedibility of it. His fatalism is not meant to be depressing rather than a commentary on the human condition being finite.