Questions to ask contractor references

-- Did the contractor surprise you with any hidden charges that you thought ought to have been included in the original bid?
-- If there were change orders, did he quote you what you think were fair prices, or did he try to stick it to you on these?
-- Did the contractor raise issues/decisions to you proactively?
-- Was the contractor responsive when you called/emailed him about issues, and did he keep track of your issues/comments without having to be reminded?
-- How often was the contractor personally on site? What did you think of his day-to-day site supervisor(s)?
-- Did the contractor start the job promptly and finish it completely without being prodded, or did he kind of meander through and disappear at points?
-- And of course: Were you impressed with the quality of the work generally? Did you have to make the contractor go back and redo things or did he do a good job the first time?