My point wasn't unreasonable complaints as much as reasonable complaints with a courteous, yet pointed, letter. It seems airlines want to resolve issues with customers if they are nice about and prefer to lose the ones that get angry since they can be problem customers. For the record, I have had flight delays that worked against me and ones in my favor(like the one that allowed me to catch my flight). The one where I got miles in my frequent flier account was a trip I should not have been on. Long, (physically) painful story.