>>103543130Because she makes the it the perfect triangular OT3!
All 3 of them have their own 3rd-wheel aspect to them, no matter how you ship them, platonically or not.
Dipper and Pacifica are the two srs ones, they take stuff seriously and are quick to anger because of it, but it also means that they're focused and can make plans together.
Dipper and Mabel are the twins, and that means that they have always known almost everything about the other one. Therefore, they have their own Pines-Twins stuff together.
And, of course, Pacifica and Mabel are both girls, which means that all the girly stuff like fashion, talking about boys (including Dipper), etc. keeps them together.
Each stick in the triangle has its own strength, and together, they make the mightiest faggot in the forest!
