Most of us don’t realize it, but in conversation, we all abide by a set of rules some philosopher of language (is that a real job?!) called the cooperative principle.

The rules are:

• Quantity
  We say just what needs to be said, no more, and no less.

• Quality
  We tell the truth and avoid saying things we can’t corroborate with evidence.

• Relation
  The things we say are relevant to the conversation.

• Manner
  We express ourselves in a way that can be clearly and easily understood.

The cooperative principle is so ingrained in our behavior that we apply it unconsciously and quickly notice any deviation from it. At the same time, it’s almost impossible to stick to it when something’s up—For example, you despise the person you’re talking to, you have a hidden agenda, or you’re just straight-up lying.