I have updated a significant number of phrases to be flagged as errors vs success by modifying those phrases individually. If a flag is detected, the message heading should be changed to "Oops" or "Success" respectively. For messages that have not been specifically flagged, the default is "Success" for redirect-messages, and "Oops" for stop-messages.
If users notice a particular message that they believe is incorrectly flagged, please report that message text. Marking this issue as Fixed.