Tony assaults Mikey Palmice in the episode. This isn't allowed in the code of conduct of the Italian mafia. One of the rules of Cosa Nostra is never raise your hands to another member. Doing so is punishable by death.
After Tony finished to play Mario Kart with his son, the screen shows two players actually playing in the game, whereas only A.J. is holding a controller, the other one being on the floor.
Tony manages to play Mario Kart 64 without applying the throttle, which would make it impossible to move. Yet he still manages to win a race by just steering, which would do nothing in the real game.
When Adriana and Chris pick up Meadow from school, it's clear in an exterior shot of her SUV that Drea de Matteo is not behind the wheel, but her stunt double is. This is also obvious because in the close-up shots De Matteo is wearing sun glasses, while in the long shots, the stunt double is not.
When Dr. Melfi and her friend are being followed by the cops, they pass the same Gulf gas station twice.
The Xanax goof is incorrect. Following Tony's fainting spell in his kitchen he goes to see Dr Melfi, who prescribes him 3 days of Xanax to 'help him through the next few days.' Therefore, during the next session on 49 minutes she asks how the Xanax had helped.
The boom is reflected in the mirror when Chris questions Tony's leadership at the Bing.
When Dr. Jennifer Melfi's friend is quoting the Doors people are strange, he says "faces look evil when you're alienated". The line is "faces look ugly when you're alone".
Tony tells Paulie that if Christopher tries to leave the hospital, to "break his other neck". Most people only have one neck.
During Tony's session, about 49 minutes in, Dr. Melfi asks if the Xanax is working. She had previously prescribed Prozac, not Xanax.