I really like Fnord's list.
It's important to remember, though, that all humans have a little bit of chaos in them. Mistakes and misunderstandings will happen. More fundamental disagreements, sometimes, too.
You can't avoid these. What's important is how you handle them (edit: by "you" I mean both people involved).
BUT trust your gut instinct. If something feels deeply wrong it probably is. Ask for advice from third parties if you're not sure. If everything seems to always go one way, that's a danger sign.
Life is pros and cons, I wouldn't expect it to be easy, but it should be pretty balanced. If it seems you're always at fault then someone is picking on you.