Choosing to leave the knightly order that raised you, and taught you all you know, is practically your family, because you no longer believe that they are true to their ideals. Independent thinking and making the hard choice when it would be very easy to smile, be happy to be 'accepted' again, and go right back to being one of the bright and upcoming Jedi of her generation. Recognising that the Jedi are losing their way, and that the argument Barriss put forward was not without merit, even if it was badly acted upon, and choosing not to be a part of it. That the very Jedi Council is blind and fearful. Giving up the resources of a Jedi, to try and make her own way in the universe. You don't think that was one of the most mature and honourable choices a Star Wars character has made in a long time? She didn't blow anything up, like Offee. She didn't linger, dissatisfied and disillusioned, until she either changed sides or fell to the dark side. She didn't play the loyal Jedi right up until the Clones blew her away. She just respectfully told them where to put their reinstatement... and walked away. And lets be honest here, the Council was just as much responsible for the whole debatacle as Tarkin, because they condemned her for something she didn't do, arguably the greatest masters of a mystical order of diplomats, detectives and peace keepers in the galaxy. The very people that mediate disputes that are sometimes system wide. If it hadn't been for Anakin and Asajj Ventress (of all people) she would have been executed for a crime she didn't commit. With Jedi consent. No, frankly walking away was the best choice any Jedi makes in the PT-era.