Marina is very concerned with how people perceive her. she was concerned with the pop star label during tfj. then she cynically gave in with electra heart and tried to be the pop star everyone thought she was supposed to be and when she didnt become ultra successful and the album was critically panned she took it to heart. and then again cynically stripped herself of the pop gloss and tried to make an album that was the antithesis of electra heart musically. and for some reason even though she says she doesnt care about success, i feel like the fact that she got concise with froot making her most critically acclaimed album and yet she still didnt attain mega success it makes her somewhat bitter. Which is why shes now saying she has other interests in life besides just writing music that she'd like to explore after this tour. I think when getting signed to a label she had ambitions of grandeur and even though shes successful she didnt make it to the level she dreamed of and that leaves her ever so slightly resentful. To me that makes her the most thin skinned, albeit not the most obvious choice.