>>85439462She was okay at first because she was just there for comedic effect and to create a nice parallel to Dipper. Then the HACK had to go and make her fuck everything up (multiple times) and each time let her get off the hook with Dipper apologizing.
I think it was best shown in two episodes, Sock Opera and Weirdmageddon part 2.
In Sock Opera, Dipper tries to get her to help him crack the case of the author but she's too busy trying to win over her new boyfriend of the week. Throughout the beginning Dipper's running in circles trying to figure out the password of the Author's computer while Mabel just makes sock puppets. Finally she reels him into helping her out, making him stop what he's doing to help her, only using spare time to solve the password problem. The computer reveals a timed password access and Dipper scrambles to solve it in time. Bill shows up and offers the password but takes Dipper's body in return and also breaks the computer. CUE ACT 3. Bill now tries to steal the journal from Mabel (who's using it for her stupid opera) while she tries to defend it. In the end, Dipper's left with broken bones, the author's shattered computer, and a near death experience. But who are you still made to feel bad for at the end? Mabel, because her plan to win a boyfriend didn't work.
The next big time we see this is in WP2. Here Mabel controls her own world and wishes for Dipper to stay there with her. Dipper wants to help the others and stop Bill in the real world so Mabel sets up a court case against Dipper and even goes as far as to make a clone of him with all of his personality drained out and hers poured in. Dipper has to actually apologize for wanting to better his life with Stanley and has to go ahead and point out times when Mabel's helped him out. Finally in the end, Mabel lets them leave her twisted world. The entire time you're supposed to be feeling for Mabel because she's losing her brother but he's doing literally nothing wrong.
