One of the things that I actually love about Bannerlord (and believe me, I complain about Bannerlord a lot) is that good relations (not even high relations) really do go a long, long way in this game. It can affect the amount of troops and the skill of troops that you recruit in towns and villages. It can affect your own fiefs prosperity. For lord it can affect whether your paying 3 cows or 8 cows for your wife. It can help you secure your own fiefs during elections. How much influence you need to recruit to an army. It affects everything in a really good way.
I really like that the relation penalties are lessened then what they did in Warband. In Warband, if you're in a war, and you will be in a war, then that your relation will be -50 by the end. In this one, it treats it like it's business and nothing personal. It's harder to get lords to like you. You really do have to somewhat go out of your way, but I think it's better. They don't require an excessively high relation for you to start seeing the benefits.