You don't have to "find positive qualities", it's a freaking game and personally I play games to have fun. That character is one of the best in terms of fun and being out of the ordinary.
In terms of ordinary characters we've plenty, plenty of content...characters like her, or Wanda or others it's like a breath of fresh air. In fact ignoring her the last x updates has been a mistake I didn't expect the author would make.
Ok, ok. Well, to each his own. I was just honestly curious what people saw in Theresa's character, if anything, that made them like her scenes.
Wanda I actually like as of a couple of updates ago, where she lets her softer side show through at the ballet studio. She is actually more interesting as a character than Angel now.
But I can't stand "holier than thou" types, especially fundamentalists like Theresa. Something about the extreme hypocrisy where she pretends to be a paragon of moral virtue and looks down on all other characters as "harlots", "sinners", or something similar, defends her son against truly awful behavior, and then when nobody is looking does the same things she criticizes.
I realize it is a game, and it's no knock on the devs, not every character has to be sympathetic, clearly Theresa's unlikability is intentional. WTHI is absolutely one of the few great games here, but to me I cringe whenever her scenes come up, just because I know I have to deal with her character one way or another. I am glad others like her, but for me, I'll take anyone else to spend game time with. Even Natasha, the lawyer, or even Roger (platonically of course), over Theresa.