Probably 30 years ago I was on a small turboprop out of basle/mulhouse to zurich which had an engine failure and rejected takeoff, lots of bad noises and fire bells, this was in the days when open cockpits were the norm and I had a great view of the action . . . I had just hassled my way onto an overbooked flight as I wanted to get home for my 2 days off for the month comissioning the new (at the time) eurostar trains out of a train yard in a red light district in strasbourg (they complained about the noise to the mayor, we hadn't got the software written to make the fans go quiet when under no load) . . . anyway I ended up on the next flight, somewhat surreal checking in again with the smell of broken engine in your clothes . . . I think I learned a lot of trust in flight crews during those years of flying in small aircraft in the winter in the mountains where you could see the flight crew at work . . . a swissair with no chocolate and no champagne was a measure to judge how rough a flight was going to be ;-) . . . kinda fun . . .
I've not had another moment or justifiable concern in well over a million miles of travel . . .