The Four Agreements by Don Miguel Ruiz:

1. Be impeccable with your word: Speak with integrity and say only what you mean.

2. Don’t take anything personally: Nothing others do is because of you; it’s a reflection of them.

3. Don’t make assumptions: Find the courage to ask questions and express what you really want.

4. Always do your best: Your best will change from moment to moment; simply do your best in every situation.