"If possible, so far as it depends on you, live peaceably with all." - Romans 12:18
This is interesting because it's an acknowledgment that it isn't going to always be possible. And it isn't going to always be up to you. You should do your best and I should do my best to live peaceably with all.
But it's true that with sinful man, it isn't always going to be possible. My sin is going to be easy to forgive by some people, and really difficult to move past for others. And others sin will be the same for me.
We struggle and strive for harmony in relationships in this life, and we should. But it's possible we won't always be able to pull it off.