What’s the hardest but best life lesson your parents taught you?

It came from my mom. We had an argument when I was 21. I told her that I resented my dad and said I hated how much he worked. She showed me the true meaning of marriage is that night by telling me if I ever said anything bad about him to her again, she will disown me. She chose him but she never chose me. She will stand by and defend the man she chose even if it means she has to disown her son.
What’s the hardest but best life lesson your parents taught you?
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