The Teen Titans HSM counter-parts attend Canterlot High as part of an exchange, and each of them has a different view and approach to life which the Equestria Girls try to share in and understand, only to find out not only do some view life differently, but life may not all be as simple as they think... Not for everyone anyway.
This especially comes in handy when a new evil threatens to takeover the world and the students must try and work together to prevent worldwide disaster.
LESSON: Some people cannot be persuaded to change. Nor can they be bought, bullied, negotiated or reasoned with. Some folks prefer to bear the grudge.