This one is hard because I like all the jinchuriki! But if I really have to pick a least favorite..I guess its...
Yagura
I hate how he was controlled by Obito so easily! And the three tails got loose from him! Then again that makes me kinda happy cause my favorite Deidara/Tobi moment was with the three tails...But yeah, I don't really have anything else to say about it..