The Return of the King
How we cite our quotes:
"Alas! there are some wounds that cannot be wholly cured," said Gandalf.
"I fear it may be so with mine," said Frodo. "There is no real going back. Though I may come to the Shire, it will not seem the same; for I shall not be the same. I am wounded with knife, sting, and tooth, and a long burden. Where shall I find rest?" (6.7.4-5)
One of the terrible things about Frodo's return to the Shire is precisely that these wounds—"knife, sting, and tooth, and a long burden"—have left marks that aren't visible to the people around him. When Frodo gets back to the Shire, it's as if he's suffering from PTSD. He has traumatic dreams and flashbacks to Mordor, and he just can't seem to get past his experiences on the Ring quest. That's the thing: the war may be over, but its effects will never be forgotten, and that's true of all wars, right? While Frodo's particular wartime experiences are unique to Middle-earth (we don't find too many soldiers at war today being asked to chuck a gold ring into a volcano), Frodo's emotions returning to the Shire, and his difficulty rejoining regular Shire life, seem totally recognizable.