Theoretically vs Realistically...

A small boy says to his father "Dad, what's the difference between 'theoretically' and 'realistically'?"

His dad thinks and then says "Right-ho son, go and ask your mother if she'd sleep with Wayne Rooney for a million quid."

The boy toddles off and comes back saying "Dad, dad, she said she would! She would sleep with Wayne Rooney for a million pounds."

"OK son," says his dad. "Now go and ask your sister the same question."

The boy toddles off, and comes back saying "Dad, dad, she said she would too!"

So then his dad says "Right, son, now go and ask your brother if he'd sleep with Wayne Rooney for a million pounds."

The son comes back excitedly saying "Dad! Dad! He said he would too!"
"Well there you have it, son," said his dad. Theoretically we could be sitting on three million quid. Realistically we're living with two whores and a chutney ferret."