What are some unusual work habits for writers?

There is a wide range of unusual habits, as what you call it, that artists do and observe - it's as wide as imagination itself. And, honestly, as a writer, I don't want to be asked this question - you better just observe a writer or artist do his/her work, and you'll discover it.

That's a fun question... Eating snacks while typing, turning the lights off, wanting to be alone in public sometimes, mastering coffee types and other caffeine oriented products, wearing a fashion of their own... Maybe :)

Some have different sleep habits that other people. 

It is about having the right atmosphere and environment for them to let the creativity inside them flow.

I always attracted with the way which the writers and the poets were holding the news paper or books in the old movies , but in general we can't said about their acts as an unusual habits 

not breaking a pen and not tearing a paper

Eating a lot of green food. Like subway says it 'Eat fresh' and feed your brain. Maybe that's what a writer does. (Just stating mine).

mostly Unusual work Habits for writer, Searching there topic of field..

A writer is an artist and usually all artists are different to some extent from normal people. 

Some like their time alone to concentrate.

Some have different sleep habits that other people. 

It is about having the right atmosphere and environment for them to let the creativity inside them flow. 

Did you know that:

J.D. Salinger wrote NAKED

Edgar allan poe wrote on strips of paper  

Stephen king always wrote on the corner