Ah yes but today there are road works or an accident, so M25 is jammed. And now you're trapped
I had the misfortune of being behind the poor person who drove their car under a jack knifed truck on the M25. We were all trapped for hours on a sunny day with everyone giving up and sitting on the grass banks near Leatherhead.
It's rarely that pleasant though. But crawling along the A25 is another kind of Hell!