When you have never missed a sorority meeting in the two years since you joined - even when you had mono.
When you forget to explain to people that your sisters who look nothing like you aren't your blood relatives.
When sisters fart on/near you and you still talk to them the next day.
You want to have 4 daughters someday and they all must join your sorority or ELSE, and if you have any sons they have to join your grandpa's/dad's/brother's/husband's fraternity.
When you are extremely hesitant to wear any other necklace, because you never take off your sorority lavalier except when swimming in the lake on retreats (if it falls off in a pool you can always retrieve it).

...
When you only have two t-shirts that don't have your letters on them somewhere- one of them has your college logo, and the other has Strawberry Shortcake on it...
When you start planning what your house will be like someday, and if your future husband doesn't like a kitchen full of strawberries, a living room with white violets, a turquoise bathroom, and a baby nursery covered in bunnies and princess stuff - TOO BAD.