* Clemenza has a line: "...it's a lot of bad blood. Sollozzo, Philip Tattaglia, Bruno Tattaglia; Garbone,..." Who the heck is Garbone?
** Seems to be a one time [[TheGhost ghost]]. He's only mentioned once in the final script and not at all in the novel. Knowing that Richard Castellano loved to add his own stuff, a ThrowItIn can't be discarded.
* After being turned down by Don Corleone for support in their narcotics enterprise, why did the Tattaglias and Sollozzo go after the Corleones? If Tom's assessment of them is to be believed, they could have been perfectly successful even without the protection the Corleones could offer, though maybe not as easily. There was no conflict of interest, as the Don pointed out. The Tattaglias could have gone on with their narcotics deal, the Corleones sticking with their own rackets, and in a few years down the line, they'd have been in a better position of strength. Going to war unnecessarily wasn't good for business.
** To them, neutrality is not good enough, because it doesn't stop prosecution. It's implied that proactive help from the Corleones network of corruption is needed in order to make it worthy. At least the other families think they are not profiting enough from it wihtout the network. Tataglia and Barzini are visibly annoyed, Vito's "selfish and unfriendly" gesture means they are taking too much risk and not gaining enough money. In addition, Tataglia is a pimp, greedy and easily manipulated (he's not invited to the wedding, he's a longtime foe), and Sollozzo is an upcoming player who is eager to climb-up and has contempt for the old Don, who "was slipping", so overthrowing the old order comes only natural to him, a generational thing, a literal Young Turk vs a Moustache Pete.
* Why did Michael have to shoot McClusky as well as Sollozzo? After shooting Sollozzo he could have disarmed McClusky at gunpoint and made his escape. Instead of being the prime suspect in the murder of a police captain he would have been implicated only in the shooting of an ex-con drug dealer, and this wouldn't have required over a year's risky exile in Sicily.
** It's premeditated murder in front of an unimpeachable (as far as anyone but the underworld cares) eyewitness. That's kind of a bad thing, and it's why Sollozzo employs McClusky as a bodyguard to begin with. It's also a direct challenge to the authority of the police, and that never ends well (so it's not like Mike or the Corleone family would be any better off, and probably ''worse'' with McClusky alive and having a hardon for them).
* So Michael has his goons wipe out the Dons of the other families. Whyn't they retaliate?
** Remember how the Turk thought that the Corleones would eventually capitulate with Vito dead? Same principle, but Micheal was better at the setup and execution.
* How in the name Christ did Tom Hagen, a non-Sicilian, in 1945, ever rank as high in the family as consigliere? HOW?
** That's what Don Corleone wanted. Who's going to tell him otherwise? In the "real" Mafia, all that stuff about blood oaths and the old country is a bunch of crap foisted off onto the junior members to make them feel like they're part of an exclusive honor society. The upper echelons see power and money as their own rewards. Look at Lucky Luciano; he handed off the "official" Mafia titles when he was locked up, then told his Italian successors that he expected them to follow his Jewish "associate"'s orders to the letter.