...your car serves as both a mode of transportation and a locker room.

... your car also serves as a sort of lost and found - shoes here, winter gear there, water bottles under the seats, bras in the glove compartment, etc.

...you have actually discussed peeing in the woods with your boss.

...entire seasons are planned around races.

...weekends are not meant for sleeping in, they're meant for long runs.

..."splits" have very little to do with flexibility.

...your entire day is ruined by uncomfortable socks.

...you often run 6 miles before having you morning coffee.

...you have strong feelings about products with names like GU and nuun. 

... you have a sock tan and it's not yet summer.

... you know that sweat is an excellent adhesive - it can glue red dust to your calves or serve as natural hairspray.

...you're more exhausted at the end of the weekend than at the end of the workweek.

...you understand that spitting is both an art (you must ensure a proper arc so as to miss your own body or your fellow runners) and a science (hydration is key here, otherwise spit gets too thick to be propelled easily and gracefully).

...it's difficult to use Facebook on your days off, because reading about other people's runs makes you jealous.

...you know exactly what and when to eat in the days leading up to a race.

...some people can name every car on the road, you can name every running shoe on the street.

...you feel energized even after your longest, hardest runs.

...you smile just thinking about running, because even when it's tough you know it's an amazing privilege, not a burden.