I have to say, something rather unusual has happened to me as well. I've had quite a bit luck with United over last 12 months or so where I did not have any reason to complain(which is a good sign, of course). A couple weeks ago, I was boarding a flight(came to the gate 30 mins prior but group 3 was boarding already), and then agent on the bridge said there was no more room on board and to start checking bags. I complied, of course - but when I got to my exit row seat(row 21), I saw PLENTY of overhead space empty around me. That really angered me, as now I was going to spend another god-knows-how-long time waiting for my bag at SFO after a long day/flight. I asked FA about it, and she said that it was GA that makes these decisions, so I found that unsatisfying and odd. So last Friday, I finally took time to write to United via Website about this experience and how GA's poor planning and perception affected me personally(and probably quite a few people as well - this entire full ORD-SFO flight departed with some EMPTY room in the overhead space). I got a call directly from United a few hours after I submitted my feedback and had a quick conversation with the guy who was very apologetic and concerned about the situation. I got offered no compensation for this incident, but he said he will track and forward the info to the right gate crew fro this flight, so I was happy with the personal call and communication that used to come in from of very impersonal emails.