Overstatement is deliberate exaggeration used for emphasis, humor, or emotional force. In poetry, it often works as a form of hyperbole, making a feeling, object, or event seem larger, louder, or more dramatic than it really is.
Poets use overstatement to sharpen a contrast, make a speaker sound passionate, or give a line a memorable spark. It is not meant to be taken literally.
Example
I waited a century for your reply,
then checked the mailbox twice before dawn.