Years ago somebody told me (and it has stayed in my mind ever since)that when stopping in a line of stationary traffic like that guy did, never pull up in the middle of the lane behind the car in front, because if the car behind you does not stop you are the jam in the sandwhich.
Always pull up to the side of the lane so that if you are rear ended it will push you forward, but you dont get crushed between two cars.
On a happyier note, I was out on my WM20 yesterday, it felt fine, and I had a nice little ride out.