When you read.

I automatically visualise characters, i read a description and it automatically flashes in my head, to thr point where i have a hard time seeing adaptations, fight club is the only film that i feel matches the images in my head that i got from reading the book

More than visualize, I am transported inti the book so to speak and swept up in it like I am actually there.

It's strange seeing a film after you've read the book it's based upon, the characters not matching the ones you visualised.. The weirdest was being a chapter or two into Irvine Welsh's 'Trainspotting', switching on the TV and a film programme was showing clips of the upcoming film! I changed channel as soon as I realised what I was seeing, but the glimpses of the actors (it was obvious which two characters I'd seen) invaded my book from that point on.

If i'm not picturing anything when reading, it means I'm not paying attention to the reading.

Depends on how it's written.

I try to visualize the story and feel what is happening in it.

A good book and healthy imagination is often better then the best movie

I visualize what I read. Oh, those bittersweet memories in my head. Oh, I want to see more.

Reading is an escape from my incredibly difficult life. I will dive in head first, putting myself in the lead character's role and experiencing whatever he does.
Also, it's interesting comparing what the author has the character doing, to what I might do in a similar circumstance.

Try Non Fiction, NERDS!

I...I can't read.

Audio books.