In the sentence below I have two parts that I can't clearly understand. First, what function does the word 'any' have? As far as I understand it is usede to give some emphasis on the word 'heavier'. Can I omit it without changing the meaning of the sentence? Second, it's the meanong of the word. Basically, I know meaning of the word but I guess it has been used as a different meaning .
Samuel Smiles, a nineteenth-century English author, wrote, “It is doubtful whether any heavier curse could be forced on man than the complete gratification of all his wishes without effort on his part, leaving nothing for his hopes, desires, or struggles.”