On LCC AirAsia they arrived at the ultimate solution to the economy class call button service issue. It is a LCC with dirt cheap fares so food and drink items are for sale (at reasonable prices). The FA's earn commissions on all in cabin sales. Consequently they request that you "please press your call button if you would like anything at any time during the flight" when they make their service announcement and they respond instantly and with a smile when you do. It's a good system.