In our Bapolic family, when the Catholics throw a party there is always beer. When the Baptists throw a party, the beer was iced down in an ancient Co-Cola ice chest in the bed of my uncle's pick-up truck. The truck was parked a half of a football field away from the other guests.
Etiquette: Bapolic families are considerate enough of each other's religions that if they have to attend each other's services, they would never attempt to take Communion. But the Baptists don't kneel during Mass, which causes problems sometimes especially at First Communions, weddings and funerals when there are a lot of people in the church. This is because the people behind them who are kneeling don't have any place to rest their elbows on the back of the pew while kneeling themselves and waiting for their turn to go up for Holy Communion. This causes a lot of discomfort on the old knees and difficulty in maintaining balance.
Nobody ever tells the Baptists that this is a problem or suggest they just sit a little forward on their seats. Bapolics are painfully polite most of the time, at least in front of people of the other religion. Otherwise they can tell jokes like my Baptist cousin who said, "You know what that ol'priest sounds like he's sayin'? 'I'mmmmm gonna walk my dog and you're gonna walk your dog tooooo-ooooo.'"
Baptists always cover their beer cans with coozies and everyone pretends they don't recognize the Budweiser logos sticking out of the top of the can. Catholics only have to cover their beer cans with coozies when they are drinking with the Baptists (out of respect) or when it's really hot outside, which it often is in South Louisiana.