Tuff is the kind of person who doesn't really believe in boundaries. She's always in other peoples business or gets herself involved with things she has no business getting involved with. She also tends to invite herself into groups and places that she was never invited to. Add to this fact that Tuff is incredibly hyperactive and quite boisterous, and you can see just how annoying Tuff is. For this reason, she tends to be ostracized, and nobody wants to be around a pushy supernerd who can't read social cues. She seems to be the target of ridicule more for this reason than because of her interests, as no one really cares what their peers are into at Lisa and Tuff's high school, as long as that person isn't pushy and obnoxious. However, she gets along very well with Lisa, who likely has the patience of a saint, as the two of them have a lot of overlapping interests. As Lisa's friend, she thinks she's been granted access to barge into the Berkley residence whenever she feels it's convenient. She also seems to have some sort of mild crush on Kent, always agreeing with whatever he says and trying to sit next to him when given an opportunity.
Tuff is an otaku extraordinaire. Or at least an otaku towards the series equivalent of "Japan". As a "Japanophile", there's no portion of the culture that she doesn't find interesting, and she often tries to adapt to the lifestyle while in East Terefirma so that the transition won't be so difficult when she supposedly permanently relocates. As you could expect, she's very into manga, anime, "Japanese" magazines, games, food, snacks, styles, music, idols and much much more. The types of games Tuff likes are typically JRPGs and the like, but she'll play anything. She has a desire to create a graphic novel of her own someday, and is pretty good at illustration.
Tuff is much less innocent than Lisa, having an understanding of all kinds of terminology and resources to some of the racier bits of "Japanese" entertainment. However, she's just not phased by it, even if she does show some excitement over cute fictional guys. This can lead to Tuff suggesting an animated movie that Lisa has no business watching. As soon as there's an inappropriate scene, Lisa usually excuses herself from the room, with Tuff never piecing it together, instead assuming that the plot was just too slow or that the writing was bad. Tuff is also really critical of media and the consumption of media, and sometimes tells fellow geeks, especially in a convention, that they're doing their fandoms an injustice. Even with Tuff being opinionated and without boundaries, she's still a typically nice person who's very fun to hang out with when you need some unpredictability in your life. She's also very caring, and when she notices a person feeling down, she will go out her way to share something she has or even buy that person something just to turn their day around.