My least favorites are both Jacob and Samara. Jacob has a very uninteresting background, has a very wooden, robotic and boring personality, the only part where he is actually shows any personality was during his loyalty mission. I never really cared for him and my conversations almost put me to sleep. As for Samara, then again her background is not really interesting and she doesn't really open up to you about her past and does not want to have a relationship with Shepard because of her code and I never really cared much for her, even Morinth seemed more interesting to me. I know many people hate on James Vega, but atleast he was sort of funny and kind of cool, and some of Shepard dialogue with him was also really funny and interesting at times. Although his accent was kind of bad. But still Vega is Definitely one of the better HUMAN Squadmates the series has had.