When...
You know the CMYK splits for a number of Pantone solids by heart
You can tell who knows what they're doing with type by looking at the spaces between words and the ends of the lines
You don't hate any colour, they all have their uses
You miss the smell of squeakers (as we used to call them) and the chalkiness of gouache
You chafe, by instinct, against using A sizes for anything... despite practicality
You pull apart cereal boxes and other packaging just to look at the spot plates on the bars
You secretly start from the premise that the client is always wrong, in some way or another
You have a love-hate relationship with printers, reps and pre-press guys (they're always guys)
You do some of your best work listening to music, not sitting in silence
You do some of your best work at 2am
You really really like Helvetica, especially Neue, but never use it
You really do care about matte displays
You have a lot of black clothes... but you're not a goth
You wish life had a history palette
You post in threads like these, instead of working on that project that's causing problems
You type your bullets