I'm afraid I must disprove your assumption - there was indeed some kind partisan activity in pretty much every country occupied by the Nazis; Italy, France, Greece, Poland, Yugoslavia, the Netherlands, just to name a few... all had partisan movements. As far as proper "revolts" go, such episodes did in fact happen from time to time - in 1943, the population of Naples rose against the Germans and managed to expel them after four days of fighting; in Poland, there was the failed Warsaw Ghetto Uprising...

Why people didn't rise up sooner? The Germans had every advantage and could have crushed such revolts very easily. By 1943, the Allies were closing in so it became possible to resist long enough to receive external support: to give you an idea, the Warsaw Uprising failed because Stalin chose not to back the rebels (despite Russian troops being a few kilometres away), and the Italians at Cephalonia did not receive any external support as well.

Also, one should not underestimate the impact of collaborationism: the Germans had made extensive use of local militias (such as the G.N.R. in Central and Northern Italy - what was then the Italian Social Republic - or the Security Battalions in Greece, the Milice in Vichy France) which posed a significant threat. I believe it is also harder to fight against other Italians, other Greeks, other French than against a foreign enemy...