After various consultations, a few failed google searches and a lot of speculation, I eventually managed to extract the truth from a native Italian.
Okay, so maybe it was an Italian from America that now lives in Florence, who was more than willing to enlighten me on the reasons for Italian ppl always appearing angry and unhappy.
The truth is, Italian men aren't very bright. They believe that any women who smile at them, are interested in them and are immediately head-over-heels in love with them. It is so bad that a man would actually follow the girl/woman and make a real nuisance of himself, so therefore all Italian women appear to be angry and unfriendly.
And this also explains the incident yesterday when I nearly danced with an Italian lady as we both kept on selecting the same path to pass one another. I started laughing, and she had a smile appear for about one fifth of a second, before forcing it away, tilting her head down, and swiftly making an exit.
So, Italian ppl are actually very friendly, just cautious. Oh yes, and it helps to keep the beggars away, as it is easy to identify foreigners - they smile.