Economics

So, yes, busy studying the foreign exchange market and I am really fascinated at how hard we as people has made it for ourselves to function economically... I mean, don't you think everything would be so much easier and welfare would be so much higher world wide if everyone just functioned on one currency and no trade barriers. Don't get me wrong, politics has it's time and place and all countries needs its' own according to faith and culture, but surely economics can be more straight forward everyone needs money and needs to buy things....Well, this is no one else's fault except our own...damn