From: KanzarisKelshen | #168
This might be because, you know, she faces a robot and a Dersite afterward. Both immune to mind control. She's really quick to KO John with it post-godding when it's convenient to her.
Tavros & Jack. Granted, Tavros is and always was a joke, and one of Tavros/Vriska probably should have been able to control Jack considering Vriska exiled the Troll universe's Jack that way and Tavros was fully capable of controlling Beq. Possibly Kanaya, too, but Vriska decided that "standing there with a stupid look on your face, waiting to be punched" was the correct opening gambit.
Terezi is certainly too high on the hemospectrum for the mindhijacking to work, so it isn't applicable to her.
And, again, her using it on John means nothing when it was the only thing she could do in that situation. Had she been capable of pushing him away from the computer and/or personally shoving Beq into the kernalsprite, she would have. Time and time again, her mind control is something she only turns to when she's not capable of physically dealing with something.
--
"Oh God, maplejet's trying to be cool again. I'll call the ambulance." - Wylvane