Joe and Petunia: Country Code

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While on a country walk, Joe and Petunia stop for a rest and discuss their walk, with Joe throwing rocks from a wall nearby: They have left tracks all through a corn field, have released some cows through a gate Joe opened, marked "Private" and their dog is now chasing sheep in the field behind them. Just then, one of the stones Joe throws shatters a bottle, much to his delight. They then see a farmer with a purple face (which they attribute to "all that country air") and think he is doing a country dance as he jumps up and down in fury. Petunia remarks that he doesn't look friendly (to which Joe says "Can't be anything we've done"), and they leave. The farmer looks out at the trail of damage they have left, and sighs "When folk go out to the country, why oh why can't they follow The Country Code?