Why is sin a thing?

I think I figured out why sin is a thing–like why a personal choice of how I live my life can be categorized as universally right or wrong. 

God gave us life but we use it to hurt him. He has certain hopes for his creation but the very creatures he has given it to are doing things contrary to his will with it. 

That seems wrong enough to give a name to it. I think maybe that is sin.

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