I'm going to keep a package that I never paid for that I mistakenly was sent from a locally owned store.
Is there a reason why you're going to keep the package?
Yes, I can't be bothered to send it back.
It's not right to keep things that don't belong to you, especially if you know who to give it back to. You should give back the package to the store by writing "return to sender" on it, because it's the honest thing to do.
Why should I return it when no one is around? I'm the only one who's going to know.
That's the right thing to do, send back something that isn't yours.