[She scowls a bit at the memories that immediately come to mind.]

They treated me like I was some fragile little blind girl who couldn't even walk around her own house without an escort. I even had to hide how strong my Earthbending is from them because it would just make things worse. [Toph shrugs.] I got to run away, though. Go off and teach the Avatar and all that.

[She pauses.]

The Avatar is basically this person who gets reincarnated a lot, and they can use all four elements. Everyone else just has one. They're still born to one specific element, but the Avatar is the only one who can learn the other three.