I suppose I fly United for two reasons.
One is I live near SFO, so United has the most non-stop options to the places I fly to (IAD, EWR, LHR, NAR, SYD, LIH, SUN, ASE, YVR, FRA, LAS, LAX, BOS, and ORD). I fly enough to make anywhere from Gold to 1K any given year, and miles for upgrades or the occasional free ticket are nice.
But the second reason is why I'm willing to cut United a lot of slack. I met my wife when she sat in front of me on an 8:05am from SFO to EWR years back and even when I'm annoyed with United that's a worthwhile memory.
Bob