I think, with a question like that, I'll hide behind as literal an interpretation as I could force onto the question.

So... William Harwood in Extra-Curricular Activity is somewhere between a self-insert and a self-parody; I gave him various aspects of myself, chiefly the ones I dislike.

And the office Donna is temping at in Uninvited is the office where I worked at the time I wrote it. Suitably adapted to the demands of the plot, of course.