Get outside of their comfort zone and try something new. You never truly grow when you're too comfortable.
You are not responsible for everyone's happiness.
You can't go through life trying to please everyone.
I look at emotional pain as something we need to go through in order to grow and learn.
You never quite know where your emotions will take you.
You can't rely on the approval of others. I used to always look for praise from my directors to reassure myself that I was doing a good job. I don't do that anymore.