disappointment box
n. A mailbox belonging to a college student (usually checked on a regular basis) which he or she normally finds empty, and thus a disappointment.
"Hey, hold on a sec, I've gotta check my disappointment box...yep, empty as usual."
disappointment box
The empty tin cans of butter cookies that are kept to store unrelated items, such as pencils and pens. Invariably opened with the expectation of cookies, the result is disappointment.
I thought there were some cookies left but it turned out to be a disappointment box.