For example: The pilot arrives too late, which is why your flight is delayed by three hours and cannot make up the time. You therefore miss your connecting flight.
For example: You have booked a cruise. Then the cruise company files for bankruptcy, and your trip does not take place.
For example: You suffer serious injuries during the flight due to turbulence, resulting in (partial) disability.
For example: You booked your connecting flight yourself and allowed only 10 minutes for the transfer, which is why you missed your connection.
For example: The travel provider had already announced its initial insolvency before your booking.
For example: You smuggled toxic substances into the aircraft.