Do not learn what is not to be learned but learn what needs to be pondered at any cost. You must read what Arthur Schopenhauer wrote in his essay on “Thinking For Oneself”.
My favourite line from his essay is “Thinking must be kindled like a fire by a draught and sustained by some kind of interest in the subject.”
Indeed, the great all time Austrian economist Henry Hazlitt wrote in his book Thinking As A Science (pdf) about the Arthur’s essay that “The last is especially recommended. It is only about a dozen pages long, and is the most stimulating essay written on the subject.”