Revealing mistake: When Xena 'dies', her pulse is checked, and they can't find one, yet you can see her pulse in her neck. (00:30:30)
Revealing mistake: If you look carefully when Neelix shoots the bins of water causing the water to rush out you can see a faucet opening on one of the bins.
Revealing mistake: The eyes of the actor playing Gideon the robot can be seen through the eye slits of the robot mask in some shots.
Revealing mistake: When Lizzy is playing the piano-forte at Rosings for Mr. Darcy and Colonel Fitzwilliam, her arm movements show that the actress isn't trying to make it look like she's playing the instrument at all.
Revealing mistake: When the plane approaches the aircraft carrier, they have to dump fuel, and the fuel comes out through the back. However it should be coming out on the wing tips. So they had a tank of water or something similar that they sprayed out through the back. (Confirmed by a Staff Seargent with the USMC who flew 8 years on a C130.)
Drew and Kate's First Date - S5-E12
Revealing mistake: Drew is supposedly naked underneath his trench coat yet you see his collar and pants underneath. But everyone is reacting as if he's actually naked.
Revealing mistake: Mitch is carrying a doll during the chase on foot – it's way too floppy to be an actual person.