accessories on an aircraft is an FO who will speak up when and as required.
And that's the rub. Fine words but your kindly thoughts to your F/O are often mis-interpreted as a wide open invitation for your F/O to constantly "coach you or advise you" in a manner known by some as "Fly-By-Mouth"
It takes skill that some do not have, to know when you should button your lips and let the captain run the ship. Constant hinting by an F/O may mean you are indeed a lousy captain or he loves to show "assertiveness" because he simply cannot stop being a back seat driver..