It always amazes me when discussions like this come up in that there are F/O's out there who think they are beyond learning. I can remember sitting on the Jumpseat as a Safety Pilot opened mouthed as a day one trainee Cadet started to debrief the Captain on HIS performance both as a trainer and his flying of the aeroplane and then disagreed with everything the Training Captain had to say during his debrief.
I couldn't believe it and it was all I could do sit there and keep my mouth shut. I've got over 1500hrs on the 737 now and still I take every opportunity to ask questions, pick up little tid-bits of information, take all advice that comes my way and use every flight I do as a tool to learn more and more. I would never dream of scoffing to a Captain who thought that things were starting to go belly up and made a few suggestions to rectify the situation. Once at the gate have a discussion, find out what had gone wrong and learn from it. I fly with some really good and experienced Captains - people like Slim Shady (although I don't actually fly with Slim I'm just using him as an example of the sort of guy it's always worth listening to) and it's a pleasure to feel that you're getting better and gaining more valuable experience every flight.
However, back to the discussion CRM has definately had a positive effect on life up the sharp end and improved safety without question. It's important to realise that we are there to work as a team to make sure all the mistakes are kept to a minimum.