Slasher/Piratepete;
While I've only once experienced problems with a high hour FO who thought he knew it all, (recent mil retiree of high mil rank, who didn't want to be line trained by some ****e civvy trained upstart, his actual words) I have found that the very experienced cockpit can land themselves in potential trouble due to being too comfortable with each other. Due to the way we work here captains can often fly together and in that case I now prefer to fly P2, that way I can behave as a co and keep a cockpit gradient in place. Its made slightly harder by the fact that I'm also management, but that can be overcome by some crew room banter before we start the day.
Tomorrow I'm off on a trip with a guy who has been a friend and colleague for 22 years, we trust each other implicitly, but he knows full well that when we report he'll have to sign for it on the grounds that if I f'*&# up as P2 its' all his fault as he signs the tech log.
Today I'm with a young guy with 700 hours, most of the sectors will be his as there is some good learning available, but its' my name in the book and my job if it goes wrong, he will get my normal crew room brief "If you think I'm wrong, shout out immediately as there may not be time later, but please don't be offended if I correct you." I've used that brief for years and never found a problem as a result.