Subway.

I have been diligently keeping those free stickers you get from subway that go towards a free sub. I had finally completed one of the sets a few months ago and today seemed like the perfect day to use it. So I went to Subway to get my delicious veggie patty sub, free subcard in hand. Upon ordering my meal the guy happened to notice my card and asked if he could see it. I gave it to him and he promptly said that it wasn't valid, some of the stickers on there were too old and had expired. Expired, I exclaimed?? What the dillio? Well apparantly the stickers expire after an unbeknownst amount of time and the color indicates the general time period they were from. I ended up buying the sub anyway and really only lost a dollar or two since you have to buy a useless soda with the subcard to make it free.