Crashing into the user's face is more professional-looking?
Honestly it is more professional looking if you hide error messages and make the game automatilly restart (with DDLS or INI files or whatever)
and then give an in-game message to the player that some error occured with your own in-game user interface instead.
If you see above 2 error messages, the second own created error message is clearly more profesional looking in my opinion, and the player shouldnot need to know what exactly caused the error, that is for the developers, and you can do something like error report to let the player send the actual reason of the error to the developers.
Especially in MMORPG's like im working on. you can not always exclude every single bug, even with massive testing cycles and beta testing.