Since I pass relatively often by central station of Naples, the difference between these two cities was the first thing I've noticed. And it was shocking.
Unbelievably clean and calm. There were young boys and girls in the evening but they were calm, too. There were some "strange" persons, and I felt not very sure when I had to pass near them. But they were not so intrusive.
This summer is stuffy in Milan, too. And the streets were dusty and hot. But it was a pleasure to walk in the streets of this city.