I bought an advent calendar, with a minifig or part of a scene behind each door. Each piece is sealed in a plastic bag and needs to be assembled. Almost every bag has an extra piece in it. Is this a mistake when the pieces are being wrapped, a little bonus (yay, 2 crowbars!) or sloppy counting?
(It's extremely Christmassy - a police station, burglars with a crowbar and axe, police officers with handcuffs - oh, and a tree with presents.)