Don't trackstand, it confuses drivers.

Just unclip one foot and put it down. Start with clipped in foot about 2 o'clock, push down when ready to go and clip in the other foot at the othe pedal comes around. You don't loose any time or start up speed that way.

As to leaning on cars, apart from all the social, safety, etc. reasons the main reason is that cyclist want 3ft clearance from cars. How can we expect drivers to give us the clearance if we violate it? Leaning on cars badly teaches drivers that its OK, in fact cyclists want to be close to cars. Yes, I realize we want the >3ft when being passed at speed, but I don't think drivers are going to learn that distinction.

Al