The feeling one gets on a Sunday night or Monday (and possibly after) following a good weekend. Symptoms are a sadness to wait a week for the weekend, a need to party/club/etc, depression when you hear a party/club/dance song, the need to go out during the week even if it means disregarding responsibilities, and others of the sort.

When you eat dirt for the first time and leave your family to build a shack in the woods