You know you're a grad student when...
You have a bookshelf worth more than your monthly rent.
"I'm married to my dissertation" is a fairly acceptable response when someone inquires about your marital status.
You show up at meetings to discuss fluffy bureaucratic proceedings of some esoteric academic club just for a few free slices of mediocre pizza.
You talk about authors like you actually know them (after all, you have stalked their personal website).
"On the marriage market" means that you are single.
You still cheers to passing the preliminary exam. And will for the entire tenure of your academic career.
Your statistical software package of choice is part of your identity construct.
Occasionally, if you're feeling spunky, you sign your name in Greek letters.
Referring to some hand waving is a clever and respectful way of pretending to know what you're talking about.
Your study groups have snack schedules.
The location of the best white boards are common knowledge. And you carry dry erase markers in your backpack.
While walking in a slightly sketchy neighborhood (because you can't afford much better), your main theft concern is loosing the notes in your backpack than the wallet in your pocket.
Grades are irrelevant.
You consider quarterly department happy hour in a dingy classroom with professors still drinking bud light to be a pretty good time.
Interacting with undergrads feels like an ethnography.
Feel free to add, Nerdfriends.
Hat Tip: This list is inspired by Second Session.