Generally, if you refuse to close, you must have a legitimate reason. As a buyer, if something is uncovered that would severely affect your enjoyment or use of the house, or your title to it, and you had no way of discovering it any earlier, you may be justified in not closing. As a seller, you are somewhat limited in why you can legitimately refuse to close, beyond not receiving funds. If you believe you have a legitimate reason, and refuse to close, you still run the risk of ultimately being found not legitimate, and then you will have to pay all of the other side’s costs that result from not closing. This could be additional mortgage costs, moving costs, or even the extra cost of buying a different house.
Before putting in an offer, be certain that you want it.