01. You know what a fixie is
02. You have gotten more than 2 or 3 flats in an 8 hour work day.
03. You know that just because your dispatcher yells at you on the radio, it's nothing personal.
04. You have a code name [i.e. 8-ball, Fire Leader, Squid]
05. You have gone the wrong way down a one-way street just to deliver a package.
06. You know how to ride a bike with one gear and no brakes, somewhat safely.
07. You know the people in the local bike shop bike first name.
08. You know that downtown on a bike is SO much faster than a car.
(Read on in the comments)