It's cliche for a geek girl to say she's a fan of Daria, but the show also has an appeal that transcends age and time in life. I was in high school at about the same time Daria was, but the series is a great character study, and also a mockery of evergreen human faults. Both of these things ensure that it remains forever fresh to me.
Daria was originally a character on Beavis and Butt-head, a fact I didn't find out until years later because Daria began her series by moving to a different town, and the tone and art style of both shows were very different. Daria herself is smart and sardonic, but also apathetic, poking fun at the human foibles around her, in the name of nothing more than doing it—but at times, a sincerity of belief does appear. Her best friend is artist Jane Lane, and Daria is similarly not "popular".
Telling stories from the point of view of the outcast is a well-worn trope, as it allows for characters to comment on the faults of society in ways more frank than the upper echelons could. But outcast characters in this role have so rarely been young girls.
Daria serves the standard dramatic purpose of the outcast, but by being a girl, and being a main character, she gives something to the female audience that we rarely get: assurance that sometimes it's okay to say when the emperor has no clothes.
At the same time, Daria is not a perfect character, and her foils are not strawmen. In fact, Daria is a great character exactly because she does have flaws, she makes mistakes. If she were merely wish-fulfillment, she wouldn't be as engaging.
There are plenty of episodes like "The Misery Chick" and "Through a Lens Darkly" that have Daria experiencing a crisis, or try to take an analytical look at her worldview. Her crush on Trent Lane, despite his many faults, also serves to make Daria more complex.
Furthermore, the people in Daria's life aren't that simple. Her mother understands her better than Daria thinks she does, and characters like Kevin, Brittany, and Mr. O'Neil are dumb but well-meaning and usually nice. Mac and Jodie are also respectable characters, and it's not tokenism that makes them that way.
Of course, you'll always find spoilsports who claim that Daria is being unnecessarily rude, the series itself is too harsh on anything it makes fun of, or the series is all about an overblown teenage persecution complex. Nope: assholes and crazies are everywhere in life, and sometimes they're right, but not always. Taking in the world compliantly is no way to deal with it, and comedy is often useful for providing this sort of challenge.
Furthermore, much comedy involves the lower groups mocking the higher groups, and that is the position that Daria herself comes from in the high school hierarchy.
Unlike, say, Lisa Simpson (who nonetheless once was a great character), Daria is mostly apathetic and apolitical, and has a few bad habits, like junk food and trashy TV. As such, we know she's not meant to be a perfect role model, but just a character like any other. It makes her annoyances feel more real to us. We can believe that when something bothers her, it bothers her, not the writers.
Our culture hasn't gotten worse, but many things about it have not changed. Yes, some parts of Daria are dated (including anything to do with computers, especially the episode "Cafe Disaffecto"), but others...yeah. We still have to deal with many of the things discussed in the series.
And by "we", I mean female viewers. I'm not saying that men can't understand this, but Daria deals with issues of body image and pressures on women that resonated with a lot of female viewers, including myself. Being nasty towards these things is not rude, but adding a needed honesty, an alternate voice to the world.
And besides that, Daria is very, very funny. Again, some things are dated, but not enough that the show can't get laughs. It's more soft chuckles than belly laughs, but these are still worthwhile.
How do I feel about Tom Sloane coming in? Parts work, and parts don't. I can see Daria and Jane going for the same type of guy, and Daria being weird around the idea of her friend having a boyfriend, and then about having a boyfriend herself, no matter how she got said boyfriend. I'm also glad the "Tom Thing" wasn't resolved speedily, and also that the series was honest about why Trent wasn't a good match for Daria.
On the other hand, Tom is such a bland character. His personality is a good match for Daria, but he's almost always right, and has none of the flaws to balance the expose of Daria's flaws that happen in the last two seasons. Their relationship feels lopsided, like Tom is only a vehicle for Daria to have new experiences and not a full character in his own right.
And sometimes the last two seasons seem written to address non-existent flaws in the earlier stories, as they press hard to suggest that Daria's attitude is not just "who she is", but the result of assorted social problems and the building of a wall around herself.
Some of these episodes are effective, but they leave a sour taste because they feel like they're trying to correct what was never a problem—Daria was never an invincible character. She was never always right. And sometimes, you just naturally grow into someone different from the norm. I like these episodes, but I prefer the immortal Daria line, "But I'm not miserable. I'm just not like them".
So, Daria has stood my personal test of time. I'm long out of high school, but I'm always going to appreciate what the show has to offer. It's about more than being a teen, more than what goes on inside that little American microcosm. It's a story about a well-developed and funny character, who gives a lot of us someone to empathize with.