Everyone has the right to pursue happiness. It's a right and privilege that every person born into this world enjoys. Those who rant about "survival of the fittest is the truth of the world," or "trampling the weak is the innate power of the strong," are either born in the Empire and raised with its complete education, or they live so blissfully that they have no connection with the rest of the world.
Humans ought to pursue happiness. Although methods vary greatly, right and wrong exist, the act of pursuing happiness is absolutely correct.
But there are also those who feel they don't deserve to pursue happiness.
The reasons are varied, most stem from inferiority and a lack of confidence, some from guilt, believing they are unworthy of happiness.
Arietta belongs to this category.