Overheard while flying through the New York Class B airspace:
Pilot: Departure ABC 795 off 14L climbing to 5000′.
Controller: Is this 725 or 795?
Pilot: What did I say?
Controller: 795.
Pilot: Oh sorry, I guess this is 725.
Controller: Don’t worry about it, I mix up call signs all day.
Pilot: Yeah, but I only have one call sign to screw up.
Ed Abrams