That is the bad thing about being in front at a light, no place to go when someone is charging up on you from behind. In that situation I stop about 10 feet short of the line so I have a little room to maneuver. With cars ahead of me, I am 10 feet behind the car, pointing toward a gap between cars, bike in first gear, both hands on the bars, right foot on brake, eyes in mirrors waiting for the car coming from behind. You can relax a little once that car approaches and stops.
Not addressing you, gnatty8, but if any of you newbs don't understand why I do all that stuff then you need to take a class and give some serious thought to what is going on out in the street.