The week prior to Thanksgiving I took a 7pm flight from SNA to LAS: my first Delta experience. Without my knowledge my seating was changed from what I had preselected. I was assigned next to the emergency exit and was immediately uncomfortable to carry this responsibility due to my physical limitations. I walked up and explained my concern to a flight attendant and was told someone would assist me with reseating once all passengers were boarded. I sat down and waited anxiously. The flight was only half full and a while after the doors were closed the attendant came by and simply advised me to pick any empty seat and move. My seat mate offered to help move my carry on and I reseated myself. The flight was ok but seemed to lack any expression of friendly customer service. Perhaps this is due to the commuter nature of this route, recent bad publicity about airline service in general, the destination, time of day. Or perhaps my expectations are too high because I usually fly north on Alaska Air which always seems to provide noticeably nice service.