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I couldn't help it, it was the way the vet said, "And what did you say was wrong with him?", as he had just demonstrated that he was pretty fit and he didn't look as if there was anything wrong with him at all. He has to have a muzzle on at the vet but he has never reacted this way before, he usually just paws at it as he tries to remove it. I was so shocked at his reaction; he might have to be sedated if this is how he's going to carry on.
I'll smack my own wrist and put a hair shirt on woofgang, but when the vet said what she said, and I think it was meant to be funny, it was funny and I defy anybody not to have laughed.