I was summarising my answer, but flyblue has put it quite perfectly. What flyblue has written is exactly why we have rest breaks in between the services. We have 8 FA's working in economy on any flight. You don't need 8 flight attendants at one go in between the 2 main services to attend to the needs of the 315 economy passengers. I work always first and business class but when I do stick my head around the curtain or come back from my break i always see at least 2 FA's down each aisle doing a water/juice/fruit/toilet clean run. Then there are the daylight flights where all the passengers are awake and need snacks (we have pot noodles for this reason), and let me tell you the poor FA's are run off their feet with that. Sometimes to some passengers they think they're being neglected because the FAs can be sooo busy attending to call bells for noodles.
I wasn't having a go at you CHIVILCOY, just stating that you don't need all the FAs walking down the aisles at once. This is also disturbing for the sleeping passengers who get bumped all the time or have torches from us shining everywhere, and this might look like we're being slack. Lately though the passengers are wising up to how much work we do have. I've had passengers come up to me to say how shocked they are to see us running back and forth without stopping (believe me it happened the other day on Hong Kong to London in Upperdeck where I was non-stop for 3 hours making sandwiches and drinks and trying to fit in serving the tech crew and cooking the breakfast which takes an hour to do. I did not sit down once to even rest my feet let alone read a mag....lol).