For me, a large part of it is that bond. The fact that no matter that I'm not very good friends with Suzy Sigma Kappa, I'd go out of my way to help her out if she needed something just because she's my sister.
That whole, when my sister's in trouble so am I song...
There's also the history and the purpose behind our sorority, and a bunch of other things too... but I'll start rambling
