Johnny fell In love, so he asks his father.
“Daddy, I fell in love and want to date this awesome girl!”
“That's a great son
Who is she?”
“It's Sandra, the neighbour's daughter”
“Ohhh I wish you hadn't said that
I have to tell you something son, but you must promise not to tell your mother
Sandra is actually your sister.”
The boy is naturally bummed out, but a couple of months later.
“Daddy, I fell in love again and she is even hotter!”
“That's a great son
Who is she?”
“It's Angela, the other neighbour's daughter.”
“Ohhhh I wish you hadn't said that
Angela is also your sister.”
This went on a couple of times and the son was so mad, he went straight to his mother crying.