Once when you tell it once when you tell her the punchline and once when she gets it.
They look at your feet instead of theirs.
Here, hold this.
He Neverlands. I really love this joke because it never grows old!
Because it's two gross! (A gross is a measurement unit for "144". So 2 * 144 = 288. Or "two gross".)
The punchline was too long
You'd think it'd be the punchline, but apparently it's funnier when the person feints...
Tell her a joke on a Monday!
Tell her a joke at Christmas