DuracellEnergizer said:

It may not be "calm" and "sarcastic" like most of Vader's other lines, but it certainly isn't the rageaholic meltdown imperialscum's making it out to be.

Since scenes before and after indicate that his primary emotion was a huge disappointment after being rejected by his son, even a slightest level of anger does not fit in there.

NeverarGreat said:

Likewise, not choking every officer on the bridge in the final scene may have been because he was too furious even to exact punishment, he simply retired to his meditation pod to scream his lungs out ;)

Wrong. Observe his body motion in the scenes on the bridge. It is extremely slow and calm. A person boiling with anger would have had a complete opposite body motion. The scene clearly indicates a big disappointment following his son's rejection. Anger has no place here and that is why delivery of "bring my shuttle" in angry fashion ruined the entire sequence for me.