Stopped in the dark on a December night on the shoulder of an interstate junction to change a tire after I had a blowout while driving. Under normal circumstances, I probably could have handled it myself, but I was getting about four hours of sleep a night because of tinnitus.

I was very nervous when a random guy stopped. My initial thought was, "Am I about to be robbed?" But it turned out that he was just a local aerospace engineer, and it was his hobby to help stranded motorists.