Now I understand. The Godfather isn't just a mob movie. It's a lifestyle. It's a character study. It's a statement. It deserves to be studied in film and society classes. I could watch it 10 times and still learn new things from each viewing. It all makes sense now.
(Edited to add: I just realized I never blogged the book. I read the book a few weeks ago, and really enjoyed it. It reads easily and it's engaging. I'm sad to discover there isn't a second or third one. Luckily, there are movies, and Mario Puzo was very involved in their making, and they're supposed to be pretty good.)
Besides the barely recognizable all-star cast (the whole time, I was thinking, "Is that Diane Keaton? It sounds like her. It looks like her. But wasn't that whole Woody Allen thing going on? It must be her...." Apparently, actors can play many roles...), I noticed a few things on this first viewing.
The book spent a lot of words endearing the characters to the reader. It is clear that the Corleones are the good guys, and they just happen to cause bodily harm to people who hurt the people they love. It's a protection racket, that's all. The film bypasses all the backstories and straightforward reasoning, but still communicates the endearing quality of these men by juxtaposing scenes.
The introduction sequence is a perfect example. There's a wedding going on outside while the Don is doing business, agreeing to avenge the brutality against a man's daughter. Between a number of these business scenes, the Don is made human, playing with the cat on his lap, greeting his grandchildren, taking family photos, and dancing with his daughter. Luca Brasi, a large, classic mobster, is seen nervously practicing the words he'll use to thank the Don for the wedding invitation. It's endearing, despite the scars on his face.
Throughout the movie, these scenes show us that the mobsters are no different than any other men. They pick up cannolis while they're out (knocking off a traitor), they make spaghetti sauce (to feed their hit men), and they appreciate get well drawings made by their grandchildren (when they survive bullet wounds). If anything, these men are noble and just, because their cause is to protect and provide for their families.
The other point, made at the very end (spoiler!), is about denial. How can the wives accept the work of their husbands? The elder Dona Corleone says very few (English) words, and Connie is a raving lunatic. But Kay is the voice of reason. She's the outsider allowed into the mob world, and she's our only chance at perspective. How can Kay accept the business? By the time she has to ask, "Is it true?" she's able to accept his lie, "No."