If you sell "golden utensils", you get 1250 money. I didn't even notice / understood those collectibles until I had played several weeks.
There is no point to block the door and trying to stockpile food. You will get money sooner if you keep your door open. It really doesn't matter if the smiley face look sad for a while. When you have more appliances, you will be overloaded with that food. (I have count how much I have and once it was over 2 500 000 portions of food.)
It took a looong time before I understood what are the "New goal" -pop ups. I don't even know how many goals I have missed.
Sorry my bad English.