Muslims are fasting between sunup and sundown: no water, food or cigarettes.
A friend had been telling his wife all about Ramadan, so she wouldn't offend anyone. Then he apparently just plumb forgot about the whole thing.
While they were waiting for a doctor's appointment, he strolls over to the water cooler, pouring himself a cup. He looks back, casually, gesturing to see if she would like some. She shakes her head, acutely aware of a roomful of people who haven't had anything to drink in hours. He takes a nice long drink.
Then his cell phone rings, so he answers it. Strolls outside for a chat, where he can soon be seen outside the window, puffing away on a cigarette. Then he came back into the waiting room, still oblivious, everyone glaring, wife mortified.