When running a photo department at a college and processing film shot by academics ... finding 35 mm film rewound into the cassette inside out - not hard to deal with, very hard to understand why the person concerned did not realise something was wrong ... finding 35 mm film rewound without the rewind button pressed, causing the camera sprockets to rip the film down its entire length on either side - also not hard to fix by see-saw developing the film in a dish.