Well, I don't have a ditch story per se, but when I was 16, I was driving my parent's car, a '68 Mustang. I came to a roundabout, and in the act of mightily showing off, I took it at about 50 mph. Unsurprisingly, the car went up and over the curb... and stayed that way, very stuck.
The problem of the stuck car was easy. Being 16 meant that I was soon surrounded by strong helpful young men who quickly pulled the car back off the curb. Still, though, there was some pretty nasty damage underneath. Luckily, it was nothing noticeable unless you looked under there, and the car still drove same as always. My parents didn't notice the damage, and life went on as before.
Years later, though, my dad still had that car, and someone, in snowy conditions, slid gently back into him. It was a minor accident. Dad was a bit confused about it, though, because although the bumper was barely bruised, there was considerable damage underneath. So odd! Keeping a wide-eyed innocent look of surprise and commiseration on my face while hearing of this was definitely one of my Great Moments in Improv Acting. 8-)