I never go on any motorways now (none in Norfolk thank goodness!) but years ago, while Prison Visiting, I was condemned to navigating that blooming M25, among many others. That was Hairy. Every few minutes everyone changes lanes to allow drivers to join from the left. Then drifts back again, only to perform the same manoeuvre a few miles further on.
No-one seemed to take a blind bit of notice of my indicators and just kept grimly speeding forwards. I was often nearly the meat in a sandwich of two huge container lorries.
Never again!