This is amusing, methinks.
I got a notice that I was behind with my VAT tax payments. I wrote my accountant confusedly: "but I always pay it right away..."
Guess what: because I habitually paid it right away when I got the papers from my accountants, I WAS PAYING TOO EARLY! So the tax department thought I was paying for the previous quarter! I have to delay payment until it's within a couple of weeks from deadline... O gawd.