According to the Catholic Bishops, scattering your ashes when you die shows "contempt" for the Catholic faith, and encourages the idea that people become "nothingness" when they die. We wouldn't want people to think that when they're dead, they're really ... well, just dead!
And even cremation, while not prohibited, is discouraged. Never mind that Italy's cemeteries are all just about full, the good Bishops have decreed that everyone has to be buried in a cemetery, even if they're cremated. Apparently, it helps hold the Catholic Church together if you bury the dead together. (No, I'm not making that up, it's the bishops' official teaching.)
Maybe they figure the world will end pretty soon. I mean, in 10,000 years or so, won't the whole surface of the Earth be a graveyard, with no place left for the living? But if there's going to be Armageddon, it probably doesn't matter, we'll be gone before the graves take over.
I particularly like this part: The Roman Catholic Church only ended its official ban on cremation in 1963, when they finally realized that cremation does not affect the soul, "nor prevents the omnipotence of God from rebuilding the body." You'd think if God created the universe, he could put a few ashes back together for His big resurrection day. But apparently it took the Catholic Church a couple thousand years to figure this out.
I guess I'd better get Grandpa's ashes off the fireplace and hike on over to the graveyard...