They’re seated next to each other the Serb having the aisle seat.
He gets comfortable for the flight and takes his shoes off, when one of the Croats says:
“Fuck, I’m thirsty, I could use a coke,” he starts to get up, when the Serb interrupts him.
“No, no, no. Sit down, we’re brothers, I’ll get you a coke.”
As soon as he’s out of sight, the Croats picks up his shoe and spits in it. Upon his return, thanks the Serb.
The other Croats says:
“Fuck, seeing him drink this, it makes me want a coke.”
“Hey it’s okay, I’ll get you a coke, we’re brothers after all,” says the Serb.
As soon as he leaves, the Croats spits in his other shoe. He comes back, thanks him.
The flight comes to an end, the Serb, putting his shoes on realizes what happened.
“Oh my god guys, c’mon! We’re brothers, we speak the same language! We lived in the same country! We have practically the same culture! The wars were 30 years ago! How long is this going to go on for?! How much longer do we have to deal with this shit!? The spitting in the shoes, pissing in Cokes!”