I also like the snowball effect: if any one of these things had been different maybe the story wouldn't have turned out that way. Every single person nudges these things further along down the path to doom. And the good things that people do are unravelled by the actions of someone else - either maliciously or with the best of intentions.

And Palpatine is one of the best things about the series. I don't know how his acting survived Lucas' dead hand but the actor does an amazing job of being creepy and paternalistic.