As you saw, Johanna volunteered herself into The Ruins because she was "mentally not there." According to several teammates, she'd been mentally checked out for a while now, and Johanna confirmed this, saying it was hard to really keep her head in the game. She looked happy when she lost, in spite of the fact that she lost $8,000 and could have made it to the end, since her whole team liked her. In her exit interview, she said she was happy to be leaving, but, "I'm gonna miss the people, even though they're all really annoying."
I was surprised by this, especially since I thought she had a hardcore crush on Kenny, you'd think that would motivate her to wanna stay, like it did on The Island. I guess she's over it. I wonder why she ended up getting so annoyed with everyone. Maybe it had something to do with Wes leaving?
No one seems to know why. I do notice she's rather quiet on all the Ruins Replays with Kenny, Ibis and Evan. She wasn't on this last one, for the first time, nor was Kenny. Instead, it was Susie, Sarah, Evan and Johnny. Susie didn't know why Johanna lost her motivation, either, or what was going on with that.
I don't know why I'm so curious, maybe because I know your experience, anywhere, is all about the people. If you don't particularly like the people, you'll want out.
Anyway. who knows.