Am I the only one who uses the date on milk cartons as an indicator for how close I am to a vacation?  When a vacation is nearing, I always take note when the milk I drink won't go bad until after I'm on vacation.  The voice inside my head says something like, "You will be long gone, self, but that milk will still be here.  Vacation is getting pretty damn close."  This is strange, I know, but I've been doing this unconsciously for years.

Watch out for ultra-pasteurized milk (aka. Super Milk).  It's great stuff, but it can skew the indicator significantly.