“When you are prepared to find fault, you will. When you are prepared to find goodness and value, you will. What you are looking for determines what you find. What you are expecting determines what you experience.”
This applies to both situations (and the way we tend to build a false construct around a “good” day or a “bad” day) and, most worryingly, people.
When you look for the bad in people, you will surely find it. It will come to you. But if you look for the good, you might be surprised. People aren’t always so terrible when you give them a chance. 🙂