But when they cross, you know the real headaches have begun.
Apparently there's only room for one eye in Chicago, and the United States, for that matter.
The question in this Eye for an "Eye" battle is, having failed to get Fox News to voluntarily change the name of its show and unable to get a temporary restraining order, can the Chicago Tribune Co. somehow make the network of Bill O'Reilly, Sean Hannity and Greta Van Susteren blink?
"Viewers are likely to assume Fox and the RedEye products owned by Tribune are collaborating, thereby causing confusion," the publishing company's suit, filed Wednesday, claimed.
But until the next court hearing, set for Feb. 26, it looks to be business as usual for the news channel's 1 a.m. weeknight talk show hosted by former Stuff magazine editor Greg Gutfeld that launched Feb. 6.
Both Chicago Tribune Co. and Fox News declined to comment. The paperwork, however, tells a story all its own.
Besides pushing Fox News for a new name, the newspaper company also seeks unspecified damages, alleging that Gutfeld's show and its Internet site "contain nearly identical content" to Chicago's free weekday RedEye tabloid and its Web presence.
The suit specifically cites such topics as Anna Nicole Smith, Barack Obama and the Oscars.
Honest. Unique stuff like that.
More to the point, the complaint says Tribune has spent nearly $4 million to promote its RedEye brand launched in 2002, which includes the free edition with a weekday circulation of 150,000 copies, as well as an Internet presence (RedEye.ChicagoTribune.com) and programming on its CLTV cable channel.
You might recall that when Fox News announced it would be calling its new program "Red Eye," this column wondered how it would feel if Tribune launched a "Hannity & Colmes" edition.
But Chicago Tribune Co., which acquired trademarks on the RedEye name and its logo for a general circulation newspaper before introducing the edition, didn't apply for trademarks with regard to television and Internet services until the day after "Red Eye" debuted.
That may not matter. The complaint said Fox admits it never bothered to check whether anyone had trademarked the name.
Since no one is commenting, it's not clear, but there are indications both sides of the dispute may be looking at what happens if they fail to prevail.
A click on FoxNews.com/redeye gets you directed to a site called simply "Greg Gutfeld's Show." There doesn't seem to be any reference to the name "Red Eye" on it.
And one of the ads on the page hints at an "if you can't beat 'em, join 'em" mentality.
Among the ads in rotation, along with Microsoft, Victoria's Secret, Monster.com, Universal Theme Parks, Levitra and others, is a solicitation to subscribe to the Chicago Tribune.
"ET," PHONE HOME: TV news outlets everywhere have to be positively giddy that Los Angeles Superior Court Judge Larry Fidler has decided to allow cameras in the courtroom for the next big show-biz murder trial, California vs. Phil Spector, which is scheduled to begin in April.
Spector, the legendary music producer known for his trademark "wall of sound" recordings and, of late, for his Sideshow Bob hair, is charged with the 2003 shooting of actress Lana Clarkson. She was star of producer Roger Corman's "Barbarian Queen" but also is recalled for a momentary but memorable appearance near the end of "Fast Times at Ridgemont High" as Mrs. Vargas, the science teacher's wife.
THE FIRST JAY OF SPRING: Sports columnist Jay Mariotti is blaming prepaid travel. He now says that his 2½-month vacation from the Chicago Sun-Times will be interrupted by a 10-day trip in April to attend the Cubs opener in Cincinnati, the Masters golf tournament in Augusta, Ga., and NCAA Final Four basketball in Atlanta.
"But that's it until May," he promised Friday by e-mail.
Phil Rosenthal's column appears Sunday, Wednesday and Friday.