Plagueis is insane, she thinks, sometimes, when she isn't so near him the thought risks surfacing to his awareness. He's completely batshit insane -
(to think he sees her as an equal. That they can be partners and allies and even friends, that reenacting the exact same lessons she suspects he was taught with, that transforming her admiration and appreciation and fondness for him into pure loathing was, of course, a necessary step.)
- to think she was the best tool for this job.
Or, well, she probably is, technically. She's just way more of a best tool than Plagueis should be bothering to spend on Gardulla the Hutt. There's something about Gardulla, about Tatooine, that she's watched guide Plagueis's intuitions more than once. He's strengthened Gardulla, supported her in founding her pod racing circuit, funded her and at the same time nudged her enemies into place to destabilize her, someday. His gaze goes farther afield when he does this, Palpatine thinks (knows), to the echoes of his little prods into his plans, tracking the results of his premonitions only that far.
Plagueis isn't very inclined to question his intuitions in depth. To look at the Force, and ask himself, so how are you betraying me today?
(There's a crack, there. An opening she can destroy him with. Not yet - and she's learned to listen to that little voice, the one that bowed to her family's will (another collection of wasteful idiots who made enemies where they could've forged tools) until, suddenly, violently, she didn't.)
This mission is below her abilities. Every mission - every errand - she's done the past year is. She'd lashed out at Plagueis, foiled one of his plans out of the same spite that led to her undermining her father at every turn, and, well. He'd punished her at the time, and he's still punishing her.
That doesn't mean she doesn't hate milk runs, especially when she should be focusing on shoring up her position in Naboo, on helping with King Tapalo's reelection, ingratiating herself - she knows Plagueis is going to nudge her into an ambassadorial position after, she's not dumb, and she resents that even as she understands it rationally, even as she craves so much more.
She hates this mediocre middle ground.
(She hates that 'not yet,' too. She hates a lot of things, a lot of people.)
And she hates Gardulla of the Besadii somehow even more than she hates Plagueis, at least in the current moment.