I did slog my way through all of The Lord of The Rings, but I found it dry, dull, and slow-moving.
Yes, Tolkien was an intricate world-builder, but I read for plot, characters, and themes. He had all of these in the trilogy, but they seemed to get lost within all of boring details of his creation.
Other books I have found dull are Pride and Prejudice, Wuthering Heights, and A Clockwork Orange.