I start noticing things that are wrong. On Law and Order and its offspring - suspects always seem to have work places or apartments with spectacular views of Manhattan. The writers know nothing of NY geograpy. In one episode, the cops drove to the Canadian border (the scenery suggested around Plattsburg, the extreme northern border) picked up a suspect and got back to NYC on the same workday. The trip, one way, is at least 6 or seven hours. I driven it. When ever there's a college student involved as a criminal or victim, they use the fictitious Hudson University as a setting. I understand not using a real college name, but with three variations of L&O, it seems that once a week, someone at Hudson is killed or raped or arrested. Can't they come up with another fictitious name?

On "Everybody Loves Raymond", if Ray and Deborah are in the kitchen, Ray's parents come to the back door. If R and D are in the living room, the parents come to the front door. How do they know?

"Barney Miller" - the cops never relieve an earlier shift, nor are they relieved by a later shift. It's New York City. I'm sure they have a 24 hour police department.

On any show, where the characters are sitting at a table, no one ever sits on the side closest to the camera. If there are four people, two people will share one side.

The interior of a house rarely matches the exterior. "Raymond" again as an example.

Seinfeld - in one episode, Kramer kidnaps an annoying dog and drops it off in Upstate New York. The dog is seen returning via the Brooklyn Bridge. The BB connects Manhattan with Long Island, not the mainland, but there are no attractive bridges connecting Manhattan to the rest of the state.

I could go on, but I'll let the rest of you add your gripes.