If you find Finns talkative, you must be a very shy person
They're nice and polite but speak slowly with attention to what they say and don't speak fast as Spaniards. They do have a sense of humor, but not very loud as southerners or mean as Russians (especially men), not sarcastical as Brits, quite a light humor, something which doesn't aim to make you lack of air out of big laughter or tries to hurt a bit the other. Something aiming to make you soflty smile, maybe let a little ''ha ha'' go but nothing excessive.
For the Italian girls, in the North they'll be quite colder and more discret than what you'd expect from southern Europeans. Some have a temperament almost as in Germanic countries (Danmark/Germany) surprisingly enough, but quite more cynical and racist, and they are not afraid of sharing their point of view, whether it is shocking you or not - they're quite frank. Also, very feminine, they like to take care of themselves, they're sophisticated.
The Southern Italian women are quite loud, always talking, complaining, joking, laughing, crying... Most expressive people on Earth maybe also generous, and they love food. Like, they really do. They overprotect their children as in many mediteranean cultures.
Physically you also see differences, in the south they have black curly hair, dark eyes most of the time, they're tanned. Up North they're really white, have clear eyes, most of the time they have light-brown hair or black hair contrasting with the skin, northerners are generally slimmer, though there's also a youth culture about sports in the south. They don't support the same teams and therefore ''tifosi'' (italian hooligans) hit each other, both between cities and between north/south. Violence is also difference - much more political and hand-to-hand in the North, in the South it's more about criminal activities, often with guns and bombs. South has been more touched by the arrival of migrants, has always been quite mixed with lots of foreign populations while the North remained quite homogenous, except for some periods.
Also in the north they speak more foreign languages (english, german, french, russian, often for work, sometimes for pleasure/culture), in the south they like dialects and English more than the rest, yet they're more communicative
It changes a lot from town to town though
Sicily is quite fitting the 'southerner' criterias, Sardinia well hmm southerner in a different way than mainland southerners
Hope it helped and well yes it's quite cliché buuuut based on the people I've met. Watch ''Benvenuti al Sud!'' If you want a movie about the cultural stereotypes!