The most frustrating bugs
What are your most frustrating bugs?
The ones that only happen in production?
The ones that only happen a tiny fraction of the time?
The ones with no error message or logs? Or the ones with huge, unintelligible errors and logs?
The ones that should have been caught by tests? Or the ones that would have never been caught by the existing test suite?
Or a combination of the above?
What are your most frustrating bugs?