"The most common problems are abuse of power, which is why I said your cousins might not run into it. Although a lot of people would say that forcing other people to adopt your culture over theirs was...already problematic. Also if you don't know enough about why some things are the way they are changing them can have their own problems, like, if Elven crops had every nutrient except one and humans were relying on their preexisting crops for that nutrient, suddenly they don't have it anymore, as a specific example. Er, take all this with a grain of salt, World History classes were never my favorites and I've forgotten a lot of information that could be relevant."