In a different life, before joining cx, I had the misfortune of flying frequently in economy on many different airlines. I find the cx business class service consistently good - however the service in economy is indifferent at best. What always strikes me is how the girls never smile and how stressed and agitated they look - it really feels like they're doing you a favour by serving you. Recently flew KLM economy and the difference in service was chalk and cheese.
Then again, one only has to go to any shop in Hong Kong and experience the indifferent service to appreciate where the problem originates. Still better than the American airlines though!
I for one would not like the cabin crew job - it must be very hard to smile and be gracious when you're tired and serving some demanding economy passenger. However, it makes a huge difference to ones overall perception of the service, and indeed the airline.