My optimism comes from the time when Marshall and Brennan were still on the Court and the time since Roberts and Alito joimed the Court. It’s pretty well known that O’Connor and Kennedy were put off by the unfriendly nature of the two remaining lib titans. On the other hand, Kennedy has gone to the right in several areas since Roberts joiined. There is nothing to suggest that Sotomayor is a Roberts and there are a few things that suggest she is a Marshall.That is where the optimism comes from.
Well different lineups mean different dynamics. Not sure how much Kennedy is swayed by Roberts if at all.
Geniality is part of the court’s mindset. Scalia vehemently disagrees with Ginsberg’s approach, but he is very nice and personable with her. That’s the model of the court now.
I have no insight into the relationships on the SC or their impact if any.