This may not be the answer you were expecting...

For the answer to this, you have to look at your contract. The contract is the legal agreement you have made with the seller. Most contracts have certain contingencies where a cancellation is acceptable. To cancel for reasons other than that, there are often consequences and such a decision should not be taken lightly.

Keep in mind that while you have been preparing to close the transaction, the seller has taken his home off the market and may have entered his own contract to purchase a home. This can create a chain of sales and purchases, all depending on you to fulfill your obligation. If you do not fulfill the contract, your decision may affect many more people than just one seller.

For the legal consequences of canceling a contract, you may have to consult an attorney.