Most floppy cables don't have a key so the plug can be rotated 180 degree's (or upside down) and still be inserted.  Even some IDE cable's can be turned and insterted if they don't have a bump or key on them.  That's why you always have to make sure pin 1 goes to pin 1.  Red stripe on the cable marks pin 1 side of the connector  and pin one will be marked on the motherboard with a 1 next to the IDE connector.  Hope I didn't confuse ya.