You have to watch this video a few times to see what sets Judge Judy off -- it looks like the guy laughs too loudly or something. It's very rare for Judge Judy to interact with the "audience", since they are all actors (extras) paid to be there.

FREQUENTLY ASKED QUESTIONS:

1. What did the guy do?
He laughs quite loudly when the rest of the audience is quiet. It may not seem that loud to you, but keep in mind that the audience probably isn't mic'd very well, so it was probably much louder to Judy. He's only sitting maybe 15 feet from her, after all.

2. Why did they keep the clip in the episode and not just cut it?
Probably because it makes Judge Judy look more tough and no-nonsense.

3. What do you mean, paid extra? The audience is real people!
Many television shows film with an audience of total strangers, such as sitcoms. They want the audience reactions for laughs, etc. But you never see that audience. On Judge Judy, they use "extras" -- actors that don't speak. Extras usually get about $100 per day of filming and are not usually in a union.

4. Why do they use extras and not real people?
It allows them to control the look of the people in the audience. They can say to the background casting director, "we need well-dressed people aged 30-60" and the agencies send only people that match that description. Also, as someone else pointed out, they can fire people they don't like :)

5. She's not a real judge! She can't do this! or
5. She's a real judge! People should respect her! or
5. How can a real judge talk to people like this?
Judge Judy was a real judge in New York, and in the early 90's signed a deal to be a Judge on this TV show. She may not be an official Judge anymore, but at least she used to be a real one. The show is considered "arbitration" -- both sides agree to participate and agree to be bound by her rulings. She runs the courtroom somewhat similarly to a real courtroom, in that she won't hear hearsay (evidence presented by someone who isn't there, like 'he said i should do it')

6. How can she force people to pay if she's not a real Judge?
Both parties agreed to be there. But anyway, the monetary rewards are paid for by the production company, which is why people aren't usually that put out at the end of the episode when the Judge has ruled against them.

7. Are the cases real?
Yes, they are. People apply to be on the show, and the production also goes through small claims court filings to find possible cases. They try to choose interesting or controversial ones, not just really dull ones. People are encouraged to exaggerate a little bit, of course. Thanks to editing, uninteresting parts can also be cut out of the broadcast.

8. Sometimes it looks like the parties are staring right at the camera. How can they be, if they are looking at Judge Judy?
If you look very carefully, you'll see there's a large hole in the wall directly above Judy's head. This is where the television cameras are. The parties may be looking at Judy but it looks almost like they are looking right at the cameras