Some Hoarders might have stacks of food saved for a "rainy day". Even when the food no longer could be used, it continues to be saved.

1. Seems straight forward to most people, if food is not longer edible, you dispose of it. For as the hoarder it may seem like a waste. But the thing is that it's more of a waste to buy in quantities even a family of 10 wouldn't be able to keep up with.
2. If you have that coupon ready to buy even more of the same ask yourself why? Is it to save yourself some money? If so, ask yourself if you wouldn't be saving more by not buying what you already have.
3. You may feel that good deals are hard to come by. That if something is on sale you have to act on that or it will be a wasted opportunity. But those deals often involve buying more than you usually would, for what a few dollars less?
   Things won't run out and if they do it won't be the end of the world. This society is all about consumption and changing what is on offer to keep customers occupied spending their money. You will get a new chance to buy coffee on sale, that is what stores do, really.