Continuity mistake: When Elizabeth Perkins sleeps over at Josh's loft, the pillows behind her head are flat and in the middle at the head of the bed. When they cut back from Josh, they are pushed up in the corner of the bed.
Continuity mistake: When Josh and Susan talk about the electronic magazine at Susan's place, the slice of pizza on the plate moves between shots.
Continuity mistake: When Josh and Susan arrive at Josh's apartment, the distance between Susan and the dinosaur changes twice between shots.
Continuity mistake: Josh stumbles into McMillan, scattering papers everywhere. Susan picks up hers and presses them against her chest. In a close-up they're tidy, yet a shot later they're all messed up.
Continuity mistake: In the equipment room, after adult Josh sings to Billy, his hair swaps from messy to brushed right before he says "Josh you look terrible."
Continuity mistake: When Billy enters the equipment room and confronts adult Josh, note the top ball's yellow sticker: it's either facing his face or away, depending on the angle.
Continuity mistake: Before adult Josh leaves home, he grabs Zoltar's card by twisting his hand around. In the close-up, the hand's position is different.
Continuity mistake: While Billy and Josh read the newspaper ads, note Billy's ice cream: the spoon stands-out longer or shorter and the pattern of the chocolate differs between shots.
Answer: Paul (John Heard) tells Josh that the serve has to cross the yellow line. When Josh calls the ball short, Paul is basically trying to cheat and claims he never said the ball has to cross the line. Although I'm trying to figure out what racquet sport their playing. It looks like they're playing on a handball court, but the racquet sports I know, the ball has to cross the short line (the yellow line in "Big") on the serve but you also serve from a service area where you have to stand in front of the short line, which they don't do.
Bishop73