Can't do right for doing wrong.
I stopped for an elderly couple once but I wasn't able to help - their handbrake had jammed on at a T-junction, leving them stranded in position to turn right. The vehicle was completely immobile, all I could do was call them a recovery agent.
I've always wondered what I'd do if I came across a broken down VW Camper van full of surfer girls but having read this post now I don't think I'll bother.
