Behind the formal mechanisms of American agreements lies personal honor—the moral commitment to keeping your word because you gave it. Americans understand keeping agreements as a matter of character, not just practical necessity. Someone who keeps difficult commitments demonstrates integrity; someone who breaks commitments when convenient reveals a character flaw.
This moral dimension gives agreements force beyond legal enforcement. Americans keep agreements partly because they see themselves as trustworthy people and want to maintain that self-image.
When you make agreements with Americans, understand that your reliability will affect how they assess your character. Breaking commitments damages not just the specific relationship but your reputation more broadly.