Good posts from Centaurus.
The best mix on the flt deck is always 2 senior guys with nothing to prove to each other ie.flat gradient,non-combatant.They neednt be friends or even know each other.Through experience and equanimity,theyre almost able to communicate telepathically,predict each others thoughts and actions.Flat gradient combatant can be as dangerous as steep gradient passive-aggressive.
Very often a stroppy FO will be testing you and will quickly come round after you pass the test.If this isnt the case and hes just a stroppy SOB,then the skipper must read the riot act or the situation spirals out of control quickly.If still no response,then offload the SOB.