Two angry neighbors
Two neighbors had been fighting each other for nigh on four decades. Bob buys a Great Dane and teaches it to use the bathroom in Bill's yard. For one whole year Bill ignores the dog.
So Bob then buys a cow and teaches it to use the bathroom in Bill's yard. After about a year and a half of Bob's cow crapping in Bill's yard; being ignored all the while, a semi pulls up in front of Bill's house.
Bob runs over and demands to know what's in the 18-wheeler.
'My new pet elephant,' Bill replies solemly.