Aside from fandom, what are your hobbies? What do you love to do?
I play D&D once a week and have for years. If I had to leave fandom for some reason, I would probably become a lot more active there, running games and writing modules and such.
Also, I'm very interested in the brain and thought and why we do what we do. I read and re-read a lot of books on the subject. A few off the top of my head:
The Geography of Thought : How Asians and Westerners Think Differently...and Why by Richard Nisbett
If you want to read about human thought, read this first. This was really interesting, well-researched, and, most importantly, shows that our assumptions about what "basic human thought" is can be completely wrong. This will help you to evalute the experimental methods and theories in other books. As the author says, "how people think" might really just be "how American college students think" depending on how the studies were conducted.
Phantoms in the Brain: Probing the Mysteries of the Human Mind by V. S. Ramachandran and Sandra Blakeslee
Ramachandran is a neuroscientist who writes about the phantom limbs of amputees, the paralysis denial of stroke victims, blindsight, and other disorders. It illumnated a lot for me about human consciousness and was very entertaining to boot.
Blink by Malcolm Gladwell.
How we make decisions. Gladwell is always worth reading. There wasn't really much synthesis from chapter to chapter (I think they were all separate essays) but the studies he cites were very valuable to me in my other reading and my own over-all synthesis.
Animals in Translation: Using the Mysteries of Autism to Decode Animal Behavior by Temple Grandin and Catherine Johnson
I'm almost finished reading this one and I've really enjoyed it. Temple Grandin is an autistic woman with a PhD in Animal Science. She believes that the way autistic people think is closer to how animals do and that we can use that to gain insight into animal behaviour. This book had so many "of course!" moments for me -- when you read something you never thought of before but realise it makes perfect sense.