I suppose it depends on one's definition of "unwritten bad blood." My definition is apparently different from the one quoted. Joe and I have more than a few differences of opinion - some of them based on LDM "facts" and others based on personality differences between us.
The nice thing is that we've SPOKEN together about those things many times and we each know where the other stands. I think anyone who knows me and knows Joe has seen where most of our differences exist WRITTEN - you just have to follow all our conversations to pick up on it.
My definition of "bad blood" involves having no interest in meeting, speaking or otherwise associating with someone. I don't play games - it takes too much effort to be underhanded and backstabbing - if there's "bad blood" between me and anyone based on my definition, both sides know it.
To be quite honest, I'm a REALLY easy going person. Offhand I doubt there are more than 5 people in my life who I would ever consider that there was "bad blood" between us. You gotta really do something nasty to me to tick me off

. Physical threats are most often what will do the trick.