Jesus says(specifically in the context of serving others): If ye know these things, happy are ye if ye do them. John 13:17
We talk about this verse when we are angry.
When you are not obeying God, you will be unhappy.
What does God say will make us happy?
We also talk about this verse when we see other unhappy, unruly children.
Why is that child unhappy? (He probably doesn’t know what God says about being happy…)