I was mostly intimidated by the thought of writing Tempus, which is why he never appeared in any of my fics until recently, and then they were very short appearances. I have no trouble with Lois and Clark (although others might think differently) Jimmy is no problem and I can swing into Perry's Southern speech pattern without any trouble (possibly because I learned to talk in North Carolina, and every now and then I catch myself doing a little bit of a Southern drawl.) Interestingly enough,, however, the supporting character I most love to write is Bill Henderson. Somehow, I seem to be able to get right inside his head and think just like him, which is scary when you think too much about it.
Nan
