Quote from RedDuke:
Yes, carry looks very seductive. Borrow yen at basically 0 interest and invest it somewhere else. For example, Iceland where krona interest was recently as high as 12%. However once the cross moves against you, as we have seen recently, all return might vaporize. This strategy is best when used on OPM (other people money). For several years when everything is rosy, you get to pocket nice returns, once it goes negative, oh well it is clients money after all. I have seen this in way too many places by now, and this is exactly the attitude of a lot of fund managers.
However, compound interest is the 8th wonder of the world.