Well put. You state the problem very concisely! We don't understand computer systems. Like you said, We won't even understand software. What we understand is

Well put. You state the problem very concisely! We don't understand computer systems. Like you said, We won't even understand software. What we understand is a small slice of it and we make mistakes even with that. Or fail to consider some cases or scenarios. Then we put those small slices together to form a module and make the same mistakes again.