Coffee filters
Not really a gadget in itself, but truly one of the most used items in our kitchens if you happen to have a coffee machine. All disposable coffee filters are shaped like a cone and they, unfortunately, have the bad habit of closing in on themselves when you try to put them in the coffee machine.
A very annoying habit if you are just on the verge of putting in the coffee grounds, but there is an easy fix to that if you find it happens to you often. Truly, we all are skipping a step in the process of putting in the coffee filter: before even unfolding the filter, you are supposed to fold it by the creases at the side and on the bottom.
Like this, the filter will have a flat bottom to sit on and the side will be strong enough to keep it in place.