The lack of concern for any of one's responsibilities in the days (or weeks, or months) leading up to a vacation. Physical symptoms include the wearing of capris and jeans at work, flip-flops, or Uggs, and a lack of makeup or grooming. Dishes begin piling up in the sink, and the afflicted's response to most questions is: "Uh, I'll worry about that later." Can happen as early as the date of vacation planning, or as late as the hours before the flight leaves.
Yeah, I was going to wash my hair, but I figured I can do that once I get to Maui. Next month. I must be suffering from vacationitis.