So I'm sitting in shul this moring and one of the local rabbonim comes up to me with a question.
"I have to go for bloodwork," he says, "but do I really have to fast for twelve hours?"
(Never mind that Yom Kippur is 25 hours long...)
So I ask: "Is that what they told you?"
"Yes," he answers, "but I heard that in the States it's only 8 hours."
And then it dawns on me. He's looking for a heter. Like I'm supposed to say "Well The New England Journal of Medicine says it's 12 hours but JAMA and American Family Physician both proved that 8 hours is fine." Medicine doesn't work like that.
So I gave him the next best answer. "It's the same thing."
"Twelve and eight hours are the same thing?" he asks.
"Yeah, in America they work in Imperial but in Canada we're metric so it comes out to the same amount of time."
To his credit, it took only 3 seconds (I counted) for him to figure it out.