Riddle Me This #2 Answered

I annoy you when I run out
Because your mind is still racing
I can make it lovely or annoying
But you can control the spacing
I am just your point
I am mostly black and blue
I am not a part of your body
But I am an extension of you
Who am I?

I think this one was pretty easy, but I hope you at least had to think a little bit.
The answer?


Image by *godlike86, courtesy of Deviant Art

A Pen.