Cause it's supposed to be entertaining. He wants to save money by not hiring good writers.
That man was David Letterman.
Someone else runs across the stage before the curtain goes up. Then, Letterman is shown walking out onto the stage. This is his way of proving to his viewing audience that he is capable of doing this maneuver. Prove it to yourself. The "runner" always runs out of view.
David Letterman
The Late Show with David Letterman is broadcast on CBS since 1993. Currently the show is on its twentieth season with CBS. Before that Late Night with David Letterman was broadcast on NBC.
Biff Henderson has: Played Himself - Olympic Contestant Interviewer in "Late Show with David Letterman" in 1993. Played Himself - Visits Super Bowl in "Late Show with David Letterman" in 1993. Played Shoe Thrower in "Late Show with David Letterman" in 1993. Played Himself - Grocery Bagging Contest Starter in "Late Show with David Letterman" in 1993. Played Alcohol Breath Analyzer in "Late Show with David Letterman" in 1993. Played Himself - Stage Manager: Visiting Greenwood, Wisconsin in "Late Show with David Letterman" in 1993. Played Himself - Visiting the World Series in "Late Show with David Letterman" in 1993. Played himself in "Late Show with David Letterman" in 1993. Played Himself - Stage Manager Modelling for Cheese Sculpture in "Late Show with David Letterman" in 1993. Played Himself - Chocolate Referee in "Late Show with David Letterman" in 1993. Played Phone-Talking Broadway Play Visitor in "Late Show with David Letterman" in 1993. Played Himself - Academy Award Previewer in "Late Show with David Letterman" in 1993. Played Himself - Visiting Yankees Spring Training in "Late Show with David Letterman" in 1993. Played Himself - Interviewing Audience Members in "Late Show with David Letterman" in 1993. Played Himself - Thanksgiving Dinner Guest in "Late Show with David Letterman" in 1993. Played Himself - Modelling for Balloon Portrait in "Late Show with David Letterman" in 1993. Played Himself - Visits Superbowl XXXIX in "Late Show with David Letterman" in 1993. Played Himself - Quality-Assurance Questioneer in "Late Show with David Letterman" in 1993. Played Himself - Explains Climate Change in "Late Show with David Letterman" in 1993. Played Himself - Helps Amanda Peet to Calm Down in "Late Show with David Letterman" in 1993. Played Himself - Stage Manager Starting Grocery Bagging Contest in "Late Show with David Letterman" in 1993. Played Himself - Disruptive Stage Manager in "Late Show with David Letterman" in 1993. Played Himself - Hidden Camera Prankster in "Late Show with David Letterman" in 1993. Played Himself - Disruptive Staffer in "Late Show with David Letterman" in 1993. Played Himself - Slam Dunk Obstacle in "Late Show with David Letterman" in 1993. Played Himself - Model for Lego portrait in "Late Show with David Letterman" in 1993. Played Himself - Top Ten List Presenter in "Late Show with David Letterman" in 1993. Played Himself - Stage Manager in "Late Show with David Letterman" in 1993. Played Himself - Guy in Cold Open Sketch in "Late Show with David Letterman" in 1993. Played Himself - Stage Manager Interviewing Audience Members in "Late Show with David Letterman" in 1993. Played Himself - Drives a Go-Kart in "Late Show with David Letterman" in 1993. Played Himself - Female Fossil Eater in "Late Show with David Letterman" in 1993. Played Blue Card Chaser in "Late Show with David Letterman" in 1993. Played Himself - At the Indianapolis Motor Speedway in "Late Show with David Letterman" in 1993. Played Himself - Stage Manager Bringing Out Christmas Ornaments in "Late Show with David Letterman" in 1993. Played Himself - Wax Celebrity Identifier in "Late Show with David Letterman" in 1993. Played Biff Henderson in "Late Show with David Letterman" in 1993. Played Himself - Stage Manager Interviewing Audience Member in "Late Show with David Letterman" in 1993. Played Himself - Reports from the NBA Finals in Salt Lake City in "Late Show with David Letterman" in 1993. Played Himself - Topless Staffer in "Late Show with David Letterman" in 1993. Played Himself - Cookie-Searching Staffer in "Late Show with David Letterman" in 1993. Played Himself - Richard Simmons Impersonator in "Late Show with David Letterman" in 1993. Played Himself - Giving Back-to-School Advice in "Late Show with David Letterman" in 1993. Played Starfleet Recruiter in "Late Show with David Letterman" in 1993. Played Himself - Reporting from the Super Bowl in Arizona in "Late Show with David Letterman" in 1993. Played Himself - Celebrates Thanksgiving in "Late Show with David Letterman" in 1993. Played Skunk Eater in "Late Show with David Letterman" in 1993. Played himself in "Cosby" in 1996. Played Man at Beach in "CSI: Miami" in 2002. Played himself in "The New Face of Late Night TV" in 2003. Played himself in "Outlaw Comic: The Censoring of Bill Hicks" in 2003. Played Cappy in "Larry Crowne" in 2011.
David Letterman reportedly ran across the stage every night since to prove that he still "had what it took" after his quintuple-bypass surgery around the year 2000.
The Late Show with David Letterman began on August 30, 1993, and ended with his retirement in 2015. Before that, he was the host of Late Night with David Letterman from 1982 to 1993.
The duration of The David Letterman Show is 1.5 hours.
The David Letterman Show was created on 1980-06-23.
Gerard Mulligan has: Played himself in "The David Letterman Show" in 1980. Played Gerry - Gives Money-Saving Tips in "Late Show with David Letterman" in 1993. Played Himself - Former Staff Writer in "Late Show with David Letterman" in 1993. Played Somali Pirate in "Late Show with David Letterman" in 1993. Played Master Artist - Painting a Presidential Portrait in "Late Show with David Letterman" in 1993. Played Himself - Gives Green Tips in "Late Show with David Letterman" in 1993. Played Abigail Smith Adams in "Late Show with David Letterman" in 1993. Played Gerry - Green Living Expert in "Late Show with David Letterman" in 1993. Played himself in "Late Show with David Letterman" in 1993. Played Scooter Libby in "Late Show with David Letterman" in 1993. Played PC Computer in "Late Show with David Letterman" in 1993. Played Himself - Taking a Break from Picketing in "Late Show with David Letterman" in 1993. Played Snow Shovel Murderer in "Late Show with David Letterman" in 1993. Played Eliot Spitzer in "Late Show with David Letterman" in 1993. Played Karl Rove in "Late Show with David Letterman" in 1993. Played Friend of President John Adams in "Late Show with David Letterman" in 1993. Played President Bill Clinton in "Late Show with David Letterman" in 1993. Played Various Characters (1993-2004) in "Late Show with David Letterman" in 1993. Played Himself - NYPD Ride-Along with Chris Elliott in "Late Show with David Letterman" in 1993. Played Paris Hilton in "Late Show with David Letterman" in 1993. Played Himself - Movie Actor in "Late Show with David Letterman" in 1993.
The duration of Late Show with David Letterman is 1.03 hours.
For the sake of humor, most likely. He is a comedian who hosts a late night talk show, after all.