Sorry it took me so long to respond. As soon as I got back from Spain my husband's family had a reunion in Rochester, NY and I just got back from that. I was dressed...business casual I would say. Slacks, plain shirt, jacket. My cousin is a flight attendant for United and she has told me whenever I fly to dress nicely in case of an upgrade. You also MUST do that if you fly using a buddy-pass.
And as for the customer service issue, I am usually either so excited about going to Spain, or so exhausted when leaving, that I haven't really noticed any problems. The cattle-call to board the plane in Madrid was interesting. We are so used to forming orderly lines in the US. That is something to get used to.