We have our own reasons to hate certain teams, but the USMNT seems to have one major rival in each confederation:
CONCACAF - Mexico (duh)
UEFA - Italy (2006 WC, 2009 Confed Cup, Guido Judas)
CONMEBOL - Brazil (1994 WC, 1998 Gold Cup, 2009 Confed Cup, 2012 Friendly)
CAF - Ghana (2006 WC, 2010 WC, 2013 U-20)
AFC - South Korea?
OFC - n/a
I also think that we are Brazil's top rival in North America since Mexico is stronger rivals with Argentina. Germany and England are probably our next two outside CONCACAF.
This post was edited on 6/30 at 2:09 pm