If you ever decide to read the original Trilogy you will see that there was some very tragic things that happened as well.
The Shire had been conquered and the hobbits were enslaved, Merry, Pippin and Sam led the revolt that freed them.
After Aragorn died of old age (sort of) Arewen (sp), was heart-broken but no boat would take her to the gray havens so she wanders lonely in the forest forever heart-broken
The ents never do find the ent-wives
All the elves leave Middle Earth

The book has much deeper meaning than the movie