What are the UCC Gap Fillers?

At the core of UCC law is efficiency and productivity. After all, selling stuff is the heart of our economy, and the last thing we need is for lawyers and courts to get in the way of the sale and exchange of products. Unfortunately, in the real world, contracts aren't always perfect, and buyers/sellers don't always make the most clear, understandable agreements. Though some terms must always be included in a contract for the contract to be valid, under the UCC, there are 5 terms that, if missing, can be replaced with standardized terms. These standard terms fill the gaps in otherwise valid UCC agreements, which is why they are called UCC Gap Fillers:

1. If price is missing, it is replaced with a reasonable price at the time of delivery. This may seem crazy because, after all, who is to say what is "reasonable". But, if a seller overlooks including a price, then the price will be a fair market rate for whatever the product is at the time it is delivered.
2. If a place of delivery is missing, then the default place is the seller's place of business.
3. If a time is missing for either shipment or delivery, then it must be done within "a reasonable time."
4. If it is not specified when someone must pay for the goods they buy, then it must be done when and where the buyer receives the goods.
5. If a contract is for an assortment of goods (like a bunch of chocolates of different types and flavors), but it does not specify who gets to decide on the assortment, then the assortment is up to the buyer.