A classic case of lack of CRM was the Kegworth crash.
No disrespect whatsoever intended to the flight deck, because CRM was in its infancy then, and there were other serious issues with instrument readouts; but on that day, both pilots identified the wrong engine and shut down the only good engine they had.
The cabin crew and some passengers were confused when the Captain told them which engine was faulty, because they could all see it was the other engine that was in trouble.
Had this information from the cabin crew been fed into the DODAR process, the correct engine would have been identified and the emergency would have had a successful outcome.
As I say, no disrepect or Monday morning quarterbacking intended, and in fact this crash is used to teach CRM today. The main point of CRM is to use all available sources of information and all team members to process an emergency.