Because they don't like random people knocking on their doors
Me: Why is your question alarmingly specific 4: No reason.
You swimming pull
Because they are pretty and hurt you.
Cuz they're yammy!!!
By telling them knock knock jokes!
The knocking always speeds up.
Because he just came to pick up his little sister.
Booooooo, Booooooo
Someone knocking at your door for no apparent reason.
Nobody asks, 'who's there ' when you try and tell a knock knock joke.
A Jehovah's Witness.
Sounds like a pretty shady dude to me.
They don't like any witnesses.