Our commercial codes and contract law presume that only a tiny fraction of contracts, at most, need be adjudicated. If a significant number of business people violated the trust upon which our interactions are based, our court system and our economy would be swamped into immobility.
It is not by chance that in nineteenth-century America, many bankers could effectively issue uncollateralized currency because they were able to develop a reputation that their word was their bond. For these institutions to succeed and prosper, people had to trust their promise of redemption in specie. Now, as then, a contractor with a reputation for shoddy work will not prosper long.