Good CRM is about either crew member being able to make a strong point or correction to the other crew member without upsetting them by the manner in which it is done. That is it.
It is a pseudo-science introduced to aviation to compensate for 'military only' trained captains who have never been an FO in civilian aviation and for the younger generation of FOs that have never experienced any real environment of discipline and for whom the cockpit gradient is, therefore, a bit of a struggle.
In foreign airlines that employ expats good CRM also helps to compensate for the fact that the Captain is a foreigner and the FO is a National and regards it as 'his' airline and the foreign captain is, he thinks, sitting in 'his' seat.