In law, there is often a lot of grey, but the essential rules are black and white. For example, contracts require three basic elements: offer, acceptance, and consideration. If I offer to buy your house for $200,000, and you accept that price, then we have a binding contract. It is not binding if you don’t accept, or if I don’t offer to pay you anything for it (or at least give you something in exchange).
Real estate contracts throw in another layer of complexity by requiring the offer be accepted by a certain date, and then requiring waivers of any conditions be signed by a certain date. If the deadlines are missed, the offer is not accepted and cannot be enforced. It can be corrected by a new offer, or the buyer or seller confirming acceptance in writing to what is essentially a new offer. We sometimes get a bit of grief over our attention to the details on real estate contracts, but it is because the law is quite particular and we need to protect our clients’ interests. Everything has to be signed, and every change initialled, because otherwise the contract isn’t valid.