One less than what I need to make an awesome roll. So 18 when I have a crit range of 19-20 or 14 when my crit range is 15-20.
I seem to do a lot better as a GM - though it might be because I get to roll a lot more dice.
I don't really know.
I roll a 7.There is almost no game system where 7 is a good roll.