The cop takes Dan's driver's license after his accident and then later Dan says he can no longer drive because he doesn't have a license. Although the police can take a license in lieu of a cash bond, they can not take away driving privileges. Driving while waiting for a court date by using the ticket as driver's identification. Typically only the state's DMV or a judge can revoke driving privileges.
When Dan is talking to Cindy and Jim (the father and daughter that are going to syndicate his column), Mitch's chair next to Dan moves close so that Mitch's leg is touching Dan's and further away, then close, then far again to Dan's chair.
During the end credits when everyone is dancing in a circle, Marie's strap on her dress is falling down on her arm, then it cuts to a different angle and the strap is magically back up on her shoulder.
At the end the family is seen driving back from New England to New York City. Their car travels west over the Queensboro Bridge from Queens into Manhattan. It makes very little sense to enter Queens when coming from New England if traveling into Manhattan. The Triboro Bridge (now called the Robert F. Kennedy Bridge) from the Bronx to Queens can also be taken to Manhattan. Entering Queens would make the trip longer and cost an extra toll.
Dan stops for gas in New Jersey while he and the girls are driving up to the family's house. He is shown pumping gas. While it is against the law in New Jersey to pump your own gas, it is sometimes done and usually overlooked as an infraction by station staff.