I know this is more language problem, but in many applications there is a text "unexpected error occurred".
How do you get the sense (in context of UX) of this information? It makes me feel that the designer has prepared for me both expected and unexpected errors and I did something wrong and crashed the entire system, which was not even expected by its authors.
The similar is with "Unknown error occurred". Something went wrong, we don't even know what.
There are lots of posts here how an application should handle errors, should it show them to the user or hide (not only because of making a user feel losing control but also because of security reasons). I understand that in these cases the designer was "expecting an unexpected error" and maybe they ask me to report it, so they can fix the problem. This makes some sense with opensource software like Linux, Mozilla Firefox etc., which declare they are not error-proof and have dedicated bug-reporting websites or they do a memory dump and send it somewhere.
How should a (commercial, mostly) application handle "unexpected" or "unknown" errors (in case we decide to show errors to users)? Should they inform the user that not only a user has lost control, but a designer as well?
Does showing "unexpected" or "unknown" errors (or just "an error") mean that the UX is poorly designed?