For some reason this gets under my skin. I've had it happen on 1.5 hour IAH - ABQ RJ flights. I think it's simply f/as who are tired and don't feel like pulling out the cart, and I think it reflects a poor service culture.
Yes, I get that in the big scheme of the world its something that is small. Will I die if it doesn't happen? Of course not. However, if we're going to apply that criteria to all UA decisions / complaints, then really, the only thing we can count on is the plane taking off and landing safely.