EWR-BOS is usually 41-43 minutes which is something like 20 minutes at cruising altitude. I have seen anything from full service to no service on this route and I fly it often. If they do full service they maybe get to the exit row and then they have to terminate it and return the carts ... so either water/OJ for the entire Y cabin or full service for E+ ...
It's such a short flight, if you really want service then you'll have to buy F.