curious to know about other opinions

Hello everyone. I am in a Greek sorority and I was just curious about a couple things. But first, I understand that if anything is to be kept private for the sake of "secrecy", I completely understand, and therefore, you do not need to answer. I am not in an NPHC nor Panhellenic sorority, but I have always thought that every organization was very interesting and unique to their own values, interests, and preferences. I think it's so cute when I see everyone being so happy where they have found their home. I have definitely found mine and where it belongs. My first question is, why can't more sororities partner up with each other? It's completely understandable if everyone is busy and there is no time to do so between both organizations. I am the first person in my family to join Greek life and for some reason, I always felt like some sororities are super competitive against each other or don't get along with one another and I just want to know why. I know everyone should be proud to be in their organizations, but sometimes I see and hear things about others that are so mean and I wonder if that is really necessary. My second question is, what is the purpose of formals? I think it's so cute to see everyone dressed up and nice for their events, but I just wanted to know if perhaps there was ever a just for fun reason or perhaps something historically connected. Thank you! (I have comments I also wish to share on another post)