Plot hole: Lisa, Zack & Screech all talk to JB as if they have known her since she was little. However, they have only known Slater for approximately four years, so them knowing her from a little girl, as implied, wouldn't be possible.Callie415
Factual error: It seemed like they had several senior years in the show? They had the prom year when Kelly, Jesse, were there. Then they had senior year when Tori was on the show when they did the senior class rings.