Thoughts.
Something i dont undertand is train of thought. What leads it?
I know that in my case i have a very strange train of thought, and i can go from thinking about a tv show to thinking about flying squirrels. Train of thought is such an interesting thing, because once you start thinking about it, and thinking about what you're thinking  you get into a cycle of intense philosophical and complex thoughts that tend to get crazier and crazier. Sometimes you can descend into existential dilemmas. 
But that is on a rare occasion. Most of the time my brain just jumps from subject to subject thinking about all the various information in my brain. But why is it my brain keeps these subjects. A lot of the information is completely irrelevant to learning and every day life, and yet it stays stored up in my brain waiting to be a topic of intrest for when i'm trying to go to sleep. Its always when I go to sleep that my thoughts decide to rage rampant. They skitter about in my brain keeping me from sleeping, all of my regrets and worries decide to attack me as i drift off.
This post alone shows how hectic my thought process is, it jumps from topic to topic because when i talked about one thing it made me think of another and so on and so forth.
So i guess what i'm trying to say is that brains are weird, and i dont get why zombies like to eat them.