Originally Posted by
rsbob
Get a chain keeper and it will never happen again.
Back in the 90s when I was doing most of my own wrenching I learned that even a perfectly adjusted FD will still throw the chain sometimes. I equipped all my bikes with Third-Eye Chain-watchers. At the time, I didn't know of anyone else making a similar device; some other brands may be (likely are) easier to install.
But back to the topic, I've had a lot of positive experiences getting offers of help, and when I see someone else who looks like they're having mechanical trouble, I make sure to offer help.