Daria becomes upset by memories of an argument her parents had when she was a child, which may have been caused by one too many parent/teacher conferences over her refusal to socialize. She later learns that her problems as a kid were just something that comes with being smart.
The people of Lawndale just don't get Daria Morgendorffer. She's cool with that. See, Daria was born alienated, and now she's just trying to make it through high school with as little human contact as possible. Popularity, friends, activities... whatever. Daria lacks enthusiasm, but she makes up for it with sarcasm. Daria is the spin-off of MTV's most sucessful cartoon, Beavis and Butt-Head.