When George (Jason Alexander) asks Kramer (Michael Richards) if he wants to go to Queens, Kramer says yes as he's getting a drink out of Jerry's (Jerry Seinfeld) fridge. He then walks away without closing the door and in the next shot the fridge is shown with the door closed.
The second time we are in Frank's garage the handwriting on the chalkboard changes between shots: note the Gs in 'GEORGE'.
When George moves a dolly holding boxes of computers, the boxes shake like they are empty.
In the scene when George first shows up for work in Frank Costanza's garage, Lloyd Braun hands Frank Costanza a cup of coffee that is obviously empty.
Jerry comments on how well Kramer's azaleas are growing and Kramer says it's all about the mulch. Mulch has nothing to do with a plant's growth.
Kramer should have turned on the hose after hooking it up.