When the store puts all of the milk that expires in 3 days in the front and you dig back and find the ones that expire much later.
There is a good reason for that. If the old milk were in the back, then it would be expired by the time it ever got pullled out.
As someone who works at a gorcery store, it pisses me off when people reach back to get milk with a later expiry date when the ones at the front don't expire for at least a week or two. Who the fuck cares when it expires as long as it is safe to drink while you are drinking it?