Years ago, .. decades actually, when i was sitting sideways as a 727FE, a crusty old captain told me, over a beer, that when you are flying the a$$hole always sits to your left. As an FE, looking to the left, the FO with his back to you is always pandering to the Captain, laughing at saids stupid jokes. As an FO, you are stuck laughing at the Captains not so funny jokes, while trying to keep them out of trouble, wondering how on this earth did he end up in the left seat. As a Captain you end up seeing your refelction in the window.
Hopefully someday all of you will end up in the left seat. When you look to your left and see your reflection, remember where the a$$hole sits.