Possibly because Italy is believed to be the land of romance, San Valentino is not as big of an event as in the USA. In Italy San Valentino is celebrated mostly by going out for dinner with your significant other. Some would buy fiori (flowers), usually rose (roses) — always in an odd number, usually 3 or 5. Some would buy cioccolatini (chocolate candies), usually Baci Perugina.
A very popular rhyme among teens goes like this “San Valentino e’ la festa di ogni cretino che credeva di essere amato e invece e’ rimasto fregato” which means that “San Valentino is the day of every cretin who thought he was loved but got screwed up“.