Any European can tell you that you must hate your neighbours, because most likely you have fought against them. Having said that, Spain has a great relationship with Portugal and we are very similar to Italy, so there are no hard feelings.
I'd say we like less France but historically England and the Netherlands have given us the most reasons to hate them, such as the Black Legend, Gibraltar, corsaries...
Anyway, as a country which has a lot of tourism, we're used to be more cheerful and welcoming than those northern countries from Europe.
That's a theory that comes from Catalonian nationalists, I believe. Columbus was genoese, but then again Italy didn't exist till XIX.
As fellow 'American Dream' lovers, though... The entire enterprise was founded by the Spanish Crown and the sailors and ships were Spanish.