I like writing because I am one of those people who thinks of the right thing to say hours, weeks or even years, too late. That sucks in day-to-day life, but in writing you can go back and do a rewrite.
Also, because I like creating stuff. A story, a painting, drawing, virtual object in a computer, an invention, a doorway, a doggy door, a cake or loaf of bread. The process takes me out of myself as well as reading or watching the tube does. And when I'm done, I have the knowledge that there is something new in the world. Which is kinda cool. Or I have a cake, which is kinda fattening.
Historically, I have been a student, a paratrooper, a construction worker, a clerk, a cashier and so on. And for varying reasons, not overly good at any of them. What I never really thought I would be is a writer. Wanted to be, yes. Thought it possible, no.