Two physicians board a flight out of Seattle. One sits in the window seat, the other in the middle seat. Just before take-off, an attorney sits in the seat by the aisle. The lawyer kicks off his shoes, wiggle his toes, and starts to settle in, when the physician in the window seat says, "I think I'll get up and get a coke."
"No problem," says the attorney, "I'm by the aisle. I'll get it for you."
While he's gone, one of the physicians picks up the attorney's shoe and spits in it. When he returns with the coke, the other physician says, "That looks good, I think I'll have one too."
Again, the attorney obligingly fetches the drink. While he's gone, the other physician picks up the other shoe and spits in it.
The lawyer comes back and they all sit back and enjoy the flight. As the plane is landing, however, the attorney slips his feet into his shoes and realizes immediately what has happened.
"How long must this go on?" he asks the physicians. "This fighting between our professions? This hatred? This animosity? This spitting in shoes and pissing in cokes?"