You know you're addicted to FIRST when. . .
-Your hands are a permanent shade of gray/black from all the dirt and grease.
-You have a grease stain on you arm from the beginning of build season.
-You look at your clock, which says 10:32, and immediatlely think of screws.
-You haven't changed your clothes in who knows how long.
-You suffer from withdrawl when away from the machine shop.
-You start singing "I love to lathe" to the tune of "I love to laugh". (hasn't happend yet, but give it time

)
Edited to add:
-You forget to take off your safety glasses when you're out of the machine shop!