stored under the bed, unread and unworn
“But in a box beneath my bed is a letter that you never read from three summers back”
“And when I felt like I was an old cardigan Under someone's bed” - cardigan
The speaker of Tim McGraw keeps a box beneath her bed with a letter inside it, three summers of feeling the addressee never read. cardigan turns the same space around and puts its speaker in it, no longer the one storing something out of sight but the old sweater someone else has left there. What is under the bed in both songs is a thing that went unattended, and only the cardigan is ever pulled back out and worn.
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