United, in particular, has some really really bad service employees.  Of course, there are some good ones too, but United management apparently tolerates some very negative attitudes.  Just a few weeks ago I had to leave town on business, arrived at the Eugene airport 45 min. before departure with just a briefcase, waited in line at the United counter for 16 minutes and then was refused boarding on the flight because it was 29 minutes until departure and the cut-off for boarding passes was 30 min.  A colleague on the plane told me there were many seats available.  The United employee smiled with glee when she told me she would not let me board.  Plenty of time.  She threatened to call security if I did not get away from her and her counter.  All the time she had this snide little smile and oozed the sense of enjoying her power.