What’s an example of a “crucial detail” from your line of work that outsiders might notice but wouldn’t consider significant unless an insider pointed out how/why it was crucial?
Example: most bicycle front fork designs are curved so steering column axis intersects point of wheel contact, improving stability. It’s not aesthetics.
Example: Overhead power lines for electric locomotives are zigzagged to even out contact wear on the pantograph
There was an electric bike monthly rental startup that didn't realize this and had the forks on backwards (with people using them), and they didn't notice until I pointed it out. Very twitchy.