babbling in an interview

last week i had a phone screen interview. one of the questions they asked me was to design a user study for a certain tool. it was funny b/c the interviewer said that it was ok if i was silent for a couple of minutes as i formed my thoughts, but being an extrovert, i just processed my thoughts out loud as i was thinking. all in all, i think it went okay (i hate to be optimistic). the only thing that bothered me was i kept on thinking of ways to improve my user study after the interview. :P well, i'm hoping they just wanted to see how i thought on my feet and not necessarily come up with the "perfect" answer.