1. Home inspection contigency?
2. Finance contigency?
3. HOA? If the house is in an HOA, then in most states, you have several days to review the HOA. During this time, if you claim you do not like the HOA rule, then you can withdraw without penalty.
Say, if the HOA allow a front yard fence, you can claim that you dislike the neighbors to build front yard fence. If the HOA does not allow a front yard, then you can claim that you want to build a front yard fence....