Somehow this image didn't make me think about any "bad thoughts" or "black ideas" or anything like this. Maybe that's because of the "symbols" you have used: an old tree, black ravens, long haired woman. For me these are things that represent stronlgy positive thoughts. Especially the old tree - I have always regarded it as the most positive symbol ever. And when there's a stairway and a door added to the tree it intensifies the optimistic feeling cause it makes me think that the tree is someone's home - and home is also a very positive symbol.
Isn't it strange how differently we can see these things? I quess most people get the idea you have wanted to show, but as I saw this image I didn't even think it could show any bad thoughts cause all the symbols seemed so positive for me.