When Shawn first reimagines the scene where he gives Juliet Chief Vick's pashmina instead of his jacket, the pashmina is clearly on the chair. However, upon further investigation of the scene and the previous episode, the pashmina mysteriously appears and reappears on the chair throughout.
They mention George Constanza and a breakup numerous times. Georga Costanza is a character from Seinfeld. In S9E14, George has a girlfriend named Maura who refuses to accept his breakup, comparing it to a submarine launching missiles, in which both parties have to turn their keys to activate the launce sequence. Maura refuses to "turn her key", prompting George to yell, "turn your key, Maura! Turn your key!"
While Shawn is showing the investigative team where he found the young woman the night before, Lassiter asks him if his third eye is blind. In Starship Troopers, Timothy Omundson plays a psychic who literally has a third eye on his forehead.