Conflict can be an exhausting process, even when it ends well. Don't waste your energy on anything that isn't worth it to you. You may decide that an issue is merely irritating, but not worth a confrontation or negotiation. Don't back down on anything that is important to you, by any objective criteria. But don't make a conflict out of a trivial item.
People tend to paint things with a broad brush, especially when they're annoyed.
That project has caused nothing but trouble. Narrow down the contention and put a fence around it. Discuss only the specific issue, incident or problem that you want resolved now. Rather than assuming you're on opposite sides, or positions, on a single issue, make sure you correctly understand the other person's objectives. There is almost always a way that you can get what you need without damaging your opponent.