I'm not saying Naples is the least safe city in the EU, or in western Europe, by all means, but it does have a reputation for being 1) unsafe for tourists due to petty crimes like pickpocketing and 2) being run by the mafia.

This reputation might be undeserved, at least as far as technologists and startups are concerned, but it is still something that would influence my decision on whether I'd move there or not. Other tech hubs in Europe, such as Berlin and Amsterdam, does not have that kind of reputation.