A group of Americans are touring Ireland. One of the women in the group is a real curmudgeon, constantly complaining: "The bus seats are uncomfortable, food is terrible, too hot, too cold, accomodation is dreadful..."
One day, the group arrives at the site of the famous Blarney Stone. "Good luck will be followin' ya all your days if you kiss the Blarney Stone," their guide says. "Unfortunately, it's being cleaned today and so no one will be able to kiss it. Perhaps we can come back tomorrow."
"We can't be here tomorrow," the nasty woman shouts. "We have some other boring tour to go on. So I guess we can't kiss the stupid stone."
"Well now," the guide says, "it is said that if you kiss someone who has kissed the stone, you'll have the same good fortune."
"And I suppose you've kissed the stone?" the woman scoffs.
"No, ma'am," the frustrated guide responds. "But I have sat on it."