Shortly after I gained my command I had an FO (ex RAF Tornado pilot) who was clearly a frustrated Captain having spent a couple of years in the RHS. To make his 'point' he produced a teddy bear from his flight bag. He used the 'teddy bear' like a glove puppet and made it 'talk' to the Captain in a sarcastic way.
I had been a Captain for all of two days and really didn't need this twerp.
I simply said:
"Just when I thought I had seen everything, some guy shows you something new . . .)"
A simple, yet effective retort. Fortunately he calmed down. Just as well because the following two days round Europe proved highly demanding and I needed his support.
Which ever seat you are in you really must help the other pilot. Airline flying is a pure survival situation from the moment you board the aircraft.
Grown ups only please.