The flashback scene in the car with the boys is supposed to take place during a heavy snow fall, and the back window and tail lights of the car are supposed to be covered with snow, but the window is completely clear.
When Eddie and Marion are having dinner, Eddie's glass is nearly empty as he begins to tell her a joke. During the middle part of the joke, the glass is nearly full, and by the time he gets to the punch line, it is empty again.
When Eddie takes his luggage out of the car, he only gets a couple of items. He holds them in his right hand, immediately closes the trunk with his left hand. The large bag ends up on the ground, even though it never was removed.
The title of the paper that Eddie is typing is "A Sound Like Someone Trying Not to Make a Sound." As he is typing, the sentence begins with 'A Sound'. When he finishes typing, the sentence begins with 'Sound' without the article. Later in the movie when he looks at the paper the sentence begins with 'A Sound' again.