Both were surprised at how collaborative their schools turned out to be. They were mostly impressed by how smart ALL of their classmates were- which was a very different experience from their public high school that only had the same dozen or so kids with close to their academic level. S told me early on - after he made Dean’s list - that while everyone there was so smart and could do the work requested, there were always a few that could do a p-set in an hour or so, while he was with most of the kids who needed 3-4 hours to complete them, there were also some who needed 5-6 hours or so. D found the same thing, although she said at Stanford it seemed that there were many kids who had so much of their focus on one special activity (often sports-related) that they mostly spent their free time with kids from their team, or with their department. But she said within her department, kids definitely like to work together with the other kids who share the same major. Kids who are just minoring or taking a random course in an area because they were interested in it, sometimes may feel left out. But that probably happens everywhere.
At both schools, they both felt that most of the kids around them felt very lucky to be there, with a high amount of respect for their classmates. Almost everyone there will admit feeling the imposter syndrome - and because of that they respect each other’s time, they know when they need to hit the books, etc.
The real competition was for the research fellowships, but there seemed to be a lot of them and the faculty do their best to find something for kids who need / want them.