Fame
Bike messengers are the unsung heroes of the courier world. Nobody knows them, and nobody notices them (even if they're about to drive a car into them, apparently).
However, there are lots of people who worked as bike messengers who then became famous. A few of them are:
Liev Schreiber (apparently Ray Donovan knows his way around Manhattan on a bike)
Malcolm McDowell
Jennifer Aniston
Henry Miller
Rob Zombie
Marky Ramone of The Ramones
(Source)