Why Can\'t We All Just Get Along?

Two physicians boarded a flight out of Seattle.  One sat in the window seat, the other sat in the middle seat. Just before  takeoff, an attorney got on and took the aisle seat next to the two physicians.
The attorney kicked off his shoes, wiggled his toes and was settling in when the physician in the window seat said," I think I'll get up and get a coke."
"No problem," said the attorney, "I'll get it for you."
While he was gone, one of the physicians picked up the attorney'sshoe and spat in it.
When he returned with the coke, the other physician said, "That  looks good, I think I'll have one too."
Again, the attorney obligingly went to fetch it and while he was  gone, the other physician picked up the other shoe and spat inn it. The attorney returned and they all sat back and enjoyed the flight. As the plane was landing, the attorney slipped his feet into his shoes and knew immediately what had happened.
"How long must this go on?" he asked. "This fighting between our professions?  This hatred? This animosity?  This spitting in shoes and pissing in cokes?"