The shark was right. With apologies to the skinny-dipper chomped in half, the shark was only being a shark and its teeth were so very sharp, her flesh so very tender. And given the harm we’ve inflicted on the planet, didn’t we deserve some punishment? When the great beast swam out of the unfathomable waters and onto screens in the summer of 1975, it stirred up anxiety that was doubtless tinged with guilt. “See it before you go swimming,” the trailer warned, tapping into our worries while making the case for moviegoing. We had many reasons to hide in the dark.