I had a timing chain skip sprocket teeth on a Ford 302cu/in. engine due to tensioner and chain wear resulting in piston and valve damage. This was due mainly to cheap components. My wife failed to tell me of the slow loss of power as teeth were skipped over, this resulted in the maximum speed of the car being 30mph, foot to the floor. eventually it slipped enough teeth that it went into the valve interference condition, bye bye valves.
My wife told me she kept forgetting to tell me. Obviously there were no real hints to problems that made a lasting impression on her. She drove the same car with a screaming bearing in the differential, I asked her how she could drive like that, her answer was that she turned the radio up.
My buddy just threw a Timing chain through the timing case cover, this resulted in the transplant of a long block engine, the chain broke in this case.