I flew from Adelaide to Paris & returned with the same airline some 12 days later. The economy class as with all airlines is tough on long-haul flights, but this experience was made bearable by the excellent Cabin crew service on all four of my long flights. The particular flight I quoted was my the Dohar to Adelaide flight, (13.5 hours). I cannot fault the cabin crew service. I discovered one of the flight attendants was reasonably new to the job, however, she was friendly & extremely pleasant, One wouldn't have known this person was new to the job. She took the time to return with drinks etc when the service trolley ran out of whatever I requested. There was always a warm friendly smile & a willingness have a brief chat, (This I find has almost disappeared from airline service). 13 hours is a long time when traveling on one's own, so a brief conversation goes a long way. She did this despite having to deal with 2 families with young children who were a handful. Hats off to Qatar training of its cabin crew & thank you to that particular flight attendant on my return flight, (Shirlee, I think).