The first one isn't actually an advice but a friend once told me this: "We start dying when we stop being a child."
There are many things behind that advice. When we're kids we're always curious, we ask questions, we seek answers, we don't care about making mistakes, we're spontaneous, etc. I could list dozens of things. At some point in life, we stop doing those things. We stop being a kid. We stop having all those dreams we once had. That's when we begin to slowly die. In this world of grow ups fighting each other because of stupid things, I'm always trying to remind me myself to never stop being a child.
The second one is related to the Nonviolent Communication approach by Marshall Rosenberg. There's always a big difference between what someone tells us and what we understand. Most of the time we implicitly make a judgment about others' actions and that judgment is just something from our mind. Many times we get offended (or upset) by something we don't realize the other person had no intentions whatsoever to offend or upset us. In the end, it's actually an exercise of empathy: if something is upsetting or offending you, figure out why before engaging in a useless fight with someone else.