Wherein lies the pain of shipping internationally from the US? Whenever I've shipped stuff, whether through the regular postal system or the big name couriers,

Wherein lies the pain of shipping internationally from the US? Whenever I've shipped stuff, whether through the regular postal system or the big name couriers, they don't seem to care where in the world the recipient is, other than that different places call for different rates, which I suppose is fair. And eBay accounts for this too.