CHIVILCOY,
I'll add my 2 cents to what Juud already said.
To someone watching the whole biz from the outside, it may seem that CC are not working hard. But there's a lot going on behind the scenes.
In between the 1st and the 2nd service, the time is split in half for crew rest. This means that if there is a crew of 14, 7 will be resting on the first shift, and 7 on the second. Which makes at least a couple of CC per galley (except on the U/D of the 747). On AF there are bars where pax can help themselves with drinks and (depending on the flight) snacks, and can always use the call button to get someone to their seat if they need something during this time. CC then usually start preparing the 2nd service 1 hour/1 hour 30 before it starts, which is quite short if you think that some of the shorter flights (JFK, EWR, BOS, YYZ etc) have barely that time left between the services.
At the same time, CC have to take care of the F/D, the in-flight sales, filling in the tabulation forms (= counting of all alcohol on board) for US Customs, and last but not least all the safety cabin/toilets checks every 15'. Of course, provided nothing else requiring their attention has happened as well (like, say, a lady giving birth on a First Class seat, with subsequent diversion, as it happened on one of my flights at the end of September).
And now let's see it under another point of view, to understand why CC need to have some rest during the flight. Let's take a CDG-LAX flight as an example. For an 8.45 Reporting Time, it means a CC had to wake up at least at 6 to get ready, reach the airport, have breakfast (won't be having another real meal before 3 or 4 O'clock PM) and read the latest Company Memos in his pigeonhole before the briefing. 8.45 briefing, 9.05 move to the aircraft (at least 15 min) to perform all the Safety/Security and commercial checks before boarding starts at 9.45 for a 10.15 departure. The flight will be 10 to 12 hours long. Then it will be another hour and a half/2 hours before the crew are inside an hotel room between 11.45PM and 1.15AM (provided of course there are no delays or else). And he will have to suffer a 9 hours time change while he's there.
Quote from a Human Factors book:
"After 8 hours awake, the performance tends to slowly deteriorate, then quicker and quicker with symptoms of sleep deprivation appearing after 12 hours awake. These effects pile up with the the Circadian effects on performance".
But at the time of our landing, when his attention will be the most required, it will be 15 to 17 hours since our CC woke up. And we are talking the best case scenario, with a morning flight and not a night flight (like on the return flight) when the Circadian Rythms will be all wrong, adding up to the effects of fatigue.
Which leads us to the main point: fatigue. It is the primary concern in a CC's profession: to be fit for flight. Being well rested is primarily a safety duty. I would beware of an airline that primes the commercial side (not having the CC rest during a LH flight and make them perform commercial duties) because it would mean it regards the pax's money as more valuable than their safety.