I'll let the master himself answer this one:

Fun Theory, for instance: the questions of “What do we actually do all day, if things turn out well?,” “How much fun is there in the universe?,” “Will we ever run out of fun?,” “Are we having fun yet?” and “Could we be having more fun?” In order to answer questions like that, obviously, you need a Theory of Fun.

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The question is: Is this what actually happens to you if you achieve immortality? Because, if that’s as good as it gets, then the people who go around asking “what’s the point?” are quite possibly correct.