Don’t take "yes" for an answer

When people say "yes," they aren't necessarily agreeing with you. Culturally, we're conditioned to be friendly and for many people saying "no" can feel uncooperative or unkind. As a result, when people say "yes" it's hard to tell whether they are trying to placate you or whether they actually agree with you.

Never Split the Difference does a great job of explaining why you're better off pushing your counter-party to say "no" before you finalize an agreement. When people says "no" you know with a greater degree of certainty that they're sharing their true preference and what their motivation for saying "no" is. When people say "yes," it's much harder to tell.

With a "yes" before a "no," you may be leaving value on the table or running the risk that your counter-party will back out of your agreement later.