Error-Message Guidelines

Nicely written. I want to add some usability ideas to this:

- Don't show multiply modals of the same error if possible. Add something like "(# errors)" to the existing modal instead;

- If some error is not critical but possibly recurring add an option to stop showing it for this session to its view;

- Don't send users to support for errors neither they nor the support can do anything about;

- If there is an error reporting option, provide a common report template for each type instead of forcing users to explain it as they see fit with a single "explain what happened" textarea.