I don't know whether it's to do with my being left-handed, but I can never work out which way to try to turn an over-tight nut or screw. The problem increases if I have to do it from the side or underneath. I sometimes do a dry run with a screw top bottle. Or just ask Mrs Steve what to do. I have a terrible problem about once a year attaching the gas regulator to my barbecue gas bottle as it has a left-hand thread. A year is plenty enough time in which to forget what to do.