During George's dinner with his parents, when he says, "I'm a college graduate!" he sets down the pepper shaker, which he wasn't holding in the previous shot. Also, the salt shaker moves around between shots.
When George (Jason Alexander) is pushed by the low talker towards the ironing board, the iron is a dark colour. When George is holding the iron though, it's silver.
When George is eating out with his parents, the point of view over his mother's shoulder shows her holding up the menu, but from George's side her menu is seen lying on the table.
When the group saw a couple of homeless guys using the puffy shirts, a woman in the audience exclaims, "Oh my god!".
George (Jason Alexander) tells Kramer (Michael Richards) that Jerry (Jerry Seinfeld) doesn't let anyone ever use his bathroom; but we've seen George using Jerry's bathroom many times.
Jerry (Jerry Seinfeld) claims Morty (Barney Martin) has "never thrown anything out. Ever". We saw him throw the wallet in the rubbish bin in episode 4.6, The Watch (1992).
When George is pushed and grabs the iron only his thumbs are on the hot bottom of the iron. In the next scene his hands are completely covered in bandages.