Flight between Denver and Sioux Falls,SD piloted by Capt. Dan who was very friendly. Staff on this trip were very friendly....actually smiled which I never seen anymore on United. Lady taking tickets in San Diego was very rude. I was in seat 12 but 5 for boarding. When it seemed like most had boarded I attempted to do so also. She looked at my ticket and said "Step aside. I haven't called zone 5 yet. I did so and exactly 4 more people went on and then she let me go. I have flown a lot and NEVER had such a thing happen. A little person with a little power and determined to use it! Maybe doesn't seem like a big deal to you, but when all I have encountered up to this point is crabby looking people it did resonate with me. Can't your average employee smile? Do things really go better with a brusque attitude? I usually fly Delta and the people there appear to like their jobs. At any rate off putting for me. If not for Capt. Dan the flight would NOT HAVE RATED a smiley face!