Some very interesting points re: crew visibility. What is a bit disconcerting is the fact that most of you are just worried that you're not getting a glass or water served at your seat. Whilst a water service is very good practice, even if it is just as convenient (for many who love to stretch their legs) to go to the galley, there are more pressing reasons for crew to be visible in the cabin. IMO it is a safety issue and not primarily a service failure.
What I will say in defence of crew taking their crew rest is that by the end of the meal service they will have probably have been on duty 5 hours. You also have to remember that crew rest is staggered. Some of you make it sound like every crew member go for crew rest all at once.