inside my head

Step inside this head of mine, I believe that you will find. Answers to questions you have been wondering about, things you have been doing so long without.
But beware of the dark spot that you see, its the part that holds the mysterious black key.
I put all the bad and ugly things in there, and all the things i can not bare.
So as you're picking out pieces inside my head, you best remember what I had said. So step inside this head of mine, what part of you are you going to leave behind?