The hard eight bet
One thing that I was curious about while viewing this film is the significance of the hard eight bet and was surprised not to see it discussed much here.
During PSH scene Sydney was calm and cool as usual until he placed the hard eight bet. It seemed like he made the bet out of emotion. A bet he previously said was "a stupid bet". Why did he make that bet?
Was that little leak in emotion a window to his past? If PSH hit the hard eight, would Sydney have killed him? Later in the film Jimmy hit the hard eight and was killed by Sydney soon after (although there was no way of Sydney knowing that).