As far as I can tell, there wasn’t a strict class structure in the Shire. A servant (Sam), could obviously become a mayor of a city, and a class system wouldn’t have allowed that. Yet in the movie, and somewhat less in the book, they are constantly forgetting that Sam is even there. Gandalf remarks that Frodo is alone and on his own more than once. It was Aragorn, in the movie, that reminds him that Sam is with him. When Frodo returns, all the worry is on him. When it is remarked about the burden of the ring and how no one has ever been able to give it up without some sort of force, verbal or otherwise, they forget that Sam gave it up simply and without any physical or verbal force at all. Why does everyone (including the author himself, I think, from Tolkien to scriptwriters) forget about Sam?