I think some people enter into gentleman's agreement just because they don't see the need for anything more formal than that. My best friend from elementary school wouldn't dare skip out on a car payment, and my co-worker is a stand-up kind of guy. He wouldn't renege on a promise to return my motorcycle in good condition. Asking them to sign legal papers or contracts would seem wrong. But a lot of people have been burned by a gentleman's agreement, and they found themselves without a legal leg to stand on.