Comment by codebje

IMO the biggest issue was always not knowing what correct is in the first place. The vast majority of software we use, the stuff that's riddled with errors, has those errors largely because what it's supposed to do is vague and never, ever deals with edge cases. You can't formally verify your application works correctly under transient network error conditions if you never thought about what your application should do under those conditions.

Perhaps that's the same thing as what you're saying, though: we don't specify these things in detail because it's expensive to spend that much time thinking through it all, when users are largely trained to just accept crashes, glitches, inconsistencies, and the occasional sprinkle of data loss.