Hi, I'm writing a comedy that in which the main characters day starts with him splitting up with his girlfriend. He meets up with his anal-retentive best friend and they go about their day. The main character goes on griping about his lost love while the best friend tries to convince him that he doesn't need her. Eventually through a series of conflicts the main character attempts to win back his girlfriend.

The story is going to take place in a suburban lower-middle class town. I really want the characters to be able to bump into friends, acquaintances, and finally the girlfriend. Much of the comedy would also stem from the best friend's obnoxiousness and refusal to conform to social norms. So I need a populated place that would serve as the setting of the plot.

I started off thinking that I would just use the mall, but I really want to avoid rewriting Mallrats. I thought about the possibility of the best friend taking the main character to the Airport for a day of awkward people watching, but this would eliminate the bumping into friends aspect.

Any ideas would be greatly appreciated.

Well, you mentioned airport and I thought that possibly he could pick his best friend up from the airport, after the friend's vacation, and then something could happen to their car, and they may have to walk home?
Just what came to my mind.

lemdog: is this a stage play or screen play etc? Why not a day in the park? Or give them a job that gets them out there, ie. dog walker....

"Hi, I'm writing a comedy that in which the main characters day starts with him splitting up with his girlfriend. "

I've got it. You have me an idea, though it might not suit the overall demands of your storyline.

Scene: A cyclotron. A worker in the particle acceleration tube is talking his girl friend on his cell phone, when a lambda particle accidentally hits his microwave transmission beam, causing him to split up with his girlfriend, i.e. -- a quantum spit occurs, such that four different universes are created, two for each male and two for each female, in accordance with the David Deutsche theory of parallel universes, which is derived from the Everett multi worlds theory.

This might inevitably lead to all the events you described in your summary, and many, many more, causing a Rabelaisian uproar, of Picaresque proportions.