Quote Originally Posted by Ryllharu View Post
The biggest was that Ui wants to follow Yui to keep her out of trouble. Sure, she is the perfect little sister and more of a mother to the Yui than their wayward parents are, but she needs to live her own life and not be held back by her sister. If Yui wasn't so oblivious, she'd probably wish for the same thing.
I think in a previous ep, we've seen that Ui is lost without her sister. For some reason she fears rejection or is insecure when her sister isn't around and she makes up for it by being perfect in every other area. She's probably the one with the more acute psychological disorder of the show.