That the magnetic pole at the south polar region is actually a north magnetic pole (and visa versa).
It is, though I think north and south are arbitrary definitions, the nice pictures of magnetic fields that show the lines radiating out of the north and into the south aren't entirely accurate as the force doesn't move, that really relates to the motion of charged particles relative to the field. But that can switch around with the particle charges, so the poles are in a sense arbitrary (they're consistent with special relativity), but there must always be a dipole, north cannot exist without a south and vice versa. Well, there are theoretical monopoles, but they imply significant symmetry violation.
Generally, it's a lot easier on the brain if you just accept that magnetism is just some kind of magic, like electrickery.
