My dad is bipolar I and I don't have a relationship with him anymore.
Growing up as a child wasn't always bad, but no one told me he had an illness until I was much older and his rapid mood changes and change in attitude scared me so bad. Some weekends, he'd be so nice and take us places and buy us nice things. The next weekend, he would be blackout drunk, screaming at us, scaring us, telling us we we're gonna grow up and be horrible people. I now know, he was experiencing mania (good times!) and depression (bad times).
I don't hate my dad for what he did to me growing up. I wish he got help a lot sooner, which he does now, but the relationship is so damaged there is no going back. But he's my dad and I'll always love him, even if he was a really big jerk at times.