"expect" is like the word "assert". You express which invariant should always be true and therefore there should be no failure. The use of `.expect("Could not read file")` is actually wrong, because it can fail.
let mut file = File::create("valuable_data.txt").unwrap();
file.write_all(b"important message").expect("failed to write message");
And I agree with OP that .expect() is poorly named. I wouldn't raise it as an issue on the work of others who just use Rust and are stuck with it though.