Writer's Block: AAAGH!
Having all my loved ones, close friends or family disappear. That'll really freak me out. The thought of having no one to lean back on or a source of comfort is really awful >.< Though of course, the people around you can be a pain sometimes.
An abosutely silent world will come 2nd. No music. Nothing. *shiver*
And also being stuck in a tiny, claustrophobic place and never be able to escape 0_0 I'd rather be killed than be put through that!