Yes, passengers can be rather unforgiving when airlines screw them!
For me, Virgin Atlantic have remained unforgiven since the time I arrived 1 hour 45 minutes early for a LGW-UVF flight in Upper and was subject to an involuntary downgrade - and, despite two letters, to this day I have not been reimbursed the difference between the Upper Class and Premium Economy fares, which was several hundred pounds. I just didn't have time to pursue the matter, wrote off the loss and gave up on VS as a hopeless case.
The biggest beneficiary has of course been BA, who have had most of my business - and, on leisure trips, that of my accompanying girlfriend (whose ticket I usually pay for). Excluding short haul routes where VS is not an option anyway, BA has probably benefitted to the tune of £20,000 a year for the last two years.
But naturally I'm as fickle as the next punter, and of course a major uncorrected screw-up by BA would lead me into the hands of the competition very rapidly!