No spoilers but these are actual lessons taught in the actual Steven Universe movie.

• Your romantic/platonic partner leaving you or treating you cruelly does not make you incapable of being loved or loving.
• Don’t let your fear, shame, or past pain cloud from people who genuinely care about you.
• If someone is genuinely putting in effort to be honest with you then you should not view their feelings as fake.
• Don’t take your pain out on others
• Don’t assume you or someone else’s past mistakes make you incapable of change.
• There are people who can love you you and what you do. Even if you can’t find them immediately, you probably already know them.
• Happily ever after doesn’t exist, and there is always work to be done, but that should not stop you from enjoying good opportunities and good people.
• Don’t try to make or interpret yourself or someone else as somebody that they are not.
• And most importantly:
• Hydration is important when smooching.