Public transportation

Flamboyant black man to woman waiting at crosswalk: Oh, thank god for a sister! I need some money for the bus and I just know you'll help me out, little white barbie sister!

Saint Louis, Missouri

Overheard by: Margie

Conductor: Mind the gap, doors closing. (train does not move) Those naughty, naughty doors.

London
England

Overheard by: ren

Flight attendant, after landing: If anyone left a black coat, please come to the front of the cabin to claim it. (pause) Or if anyone would like to take a black coat for free.

Orlando, Florida

Woman #1: Dammmnnn girl! This metro so damn crowded!
Woman #2: Shit yeah! Too many people here.
Woman #1: Don't worry, Obama gonna take care of that.

http://eavesdropdc.blogspot.com/2008/11/metro-yes-we-can.html

Overheard by: Ian

Conductor: Everybody please be patient, we have an obstruction on the tracks. Police are working to clear it, we will continue as soon as they finish.
Young suit: We're in a 55-ton battering ram, why did we even stop?

MAX Rail
Portland, Oregon

Overheard by: Ram Das

Conductor, over intercom: Rub-a-dub-dub!

Chicago, Illinois

Lady, bumping into man: What? You're so in a rush you have to knock me down?!
Man: Sorry, I was gonna ask you the same thing.
Lady: Watch where you're going!
Man: Please leave me alone!
Lady: No! You leave me alone!

Metro
Washington, DC

Overheard by: Jim

(the road is closed for Chinese New Year parade)
Bus driver: Folks, we’ll be alright. We’re going to take a right on Sansome, a left on Broadway, and a left on Stockton. We’ll rejoin the original route at Stockton and Sacramento. Don’t worry. Everything will be alright. As long as I still get paid, it’s okay.

San Francisco, California

Gross girl: Well, that girl's bathroom wasn't that bad.
Grosser guy: Well, the flies come to the men's because they like the pee pee floor. Mmmhmm.

Metro Red Line
Washington, DC

Vaguely thuggish flight attendant: Aiiight, y'all, welcome aboard United Airlines…don't know the flight number, but we're going to Detroit, and that's all that matters.

Delayed Flight from Washington, DC

Overheard by: keeeeem