Have enjoyed (sufferred?) quite a few flights, but never something as dramatic as the O2 thingys deploying.
Was on a 707 going down into Easter Island when the wing was struck by lightning - most pax were screaming. But it really didn't affect the flight.
Short flight in Colombia where they left a door open - return to land in minutes fixed that.
Inability to land due to weather followed by return to takeoff airport - where although nothing was said, as an experienced flyer you felt they glided most of the way back
Quite a few flights where pax identified panels missing from engine cowlings, wings, etc. Again no real stress.
Many of the usual medical diversions, including some dead pax.
many a "go around" - experiences which are relatively harmless, but the effect on the pax is governed by the communication of reasons by the pilot.....
But I really think this thread highlights just how such events are unusual, even for frequent flyers.