> It was a weird experience. My colleagues just had no ability to reason about the "physics" of what computers did. I think they mostly had Rails backgrounds, and I wonder if you just don't exercise that muscle much doing Rails.

Same experience here. I feel like I'm always repeating myself when explaining to other developers why we should avoid moving data around unnecessary and prefer to operate directly in the database when necessary, specially when it comes to large data migrations. Also important is why it is bad to do a bunch of small operations instead of batching them in chunks closer to the page size (8 kB).