Scroll down to the literal prose translation of
"'O sole mio" (performed
here by Enrico Caruso) and compare that to the lyrics of
"It's Now or Never" (performed
here by Elvis Presley).
The sentiments of the two versions could not be more opposed: basically, "You are the center of my personal universe" vs. an anthem of instant gratification.
[Edited to say: Unless, of course, you're cynical enough to think that all love songs are about getting into someone's pants, no matter what the words literally say.]