We belong to a creative race of literature and language and have very distinctive qualities due to our subsequent personalities and cultures. We can identify to certain characteristics that we commonly, more or less, relate with as any other group of people. Let's list these characteristics here for 'lawlz'! I'll start. + You know you're a writer when you could easily be confused as a person with imaginary friends or a schizophrenic because you can so vividly imagine your characters to the point of watching or speaking with them. + You know you're a writer when you narrate what you're doing, aloud or silently. + You know you're a writer needlessly correct others' grammar and or typos. + You know you're a writer needlessly correct your own English teacher/professor's grammar and or typos. + You know you're a writer when the movie Stranger Than Fiction relates to you significantly more than your friends. + You also know you're a writer when you have trouble killing your characters because of Stranger Than Fiction.
You know when you're a writer when most of your rough work is written on scraps (random cardboard, tissue, receipts).
I know exactly what you mean when you say vividly imagining your characters. I have a series of stories I've been working on for about 5 or 6 years now. I now know my main character, Kelly Brink, so well I could carry on a normal conversation with him. For me, you know your a writer when you have to write so badly you get stressed out until you unload your emotions on pad of paper. Then when your done you throw away the paper.
You know you're a writer when you have zero social skills, you're really out of shape because you don't get any exercise, and you wish people cared more about what you had to say.
No! You know you're a writer because you come off odd in social situations because you're constantly thinking that would make a great story and feel guilty about it, you only exercise because you can't hold a pen and it gives you time to mull over writing without actually writing, and you have to bite your tongue when something reminds you of something you've been working on so you don't bore people with your work.