Do I call myself a Writer?

Do I call myself a writer? I do not call myself a "writer". I am the kind of person who only writes when I have too, I do not enjoy it and no one would ever see me causually writing out my thoughts. The kind of person who I consider to be a "writer" is someone who enjoys writing in blogs, writing columns and such. I know people who enjoy doing these types of things and I feel like they have the right mindset to consider them a writer, if I told a person who has a passion for writing they would probably look at me like as if I was making a joke out of it. The only thing that I use to write is twitter but not becuase I like to write, but becuase I like to express my random thought of the moment.