I think you can over-emphasive the touchy-feely, "dont hurt my feelings" aspect of this. I think realistically 99% of us approach it in a fairly practical way. Hopefully the operators we work for will have produced an SOP to help this. For example, a guide on how to intervene if there is a deviation from the correct flight path, graduating from the "Check Height" call, through to the "I have control" call.
There are huge variations in training standards, company and national cultures worldwide. As a simulator instructor, I have seen plenty of people who will either sit there fat, dumb and happy, watching the other pilot (or even watching themselves) crash the aircraft without being able to make any sort of decision, or they reach across the cockpit the second a malfunction occurs and switch off ,for example, the one good engine without any consultation. This is what we are trying to avoid with CRM. As long as we have crew who are reasonably assertive, and will speak to each other and work out some sort of solution to a problem, believe me we are 95% of the way there.