I have a cousin that I never got along with. When we were kids we always had silly arguments over everything and absolutely nothing.
In our teens, our fights got physical.
The fights were emotional and brutal. We never did it "for fun".
Over time, it got more and more obvious that we both loved fighting each other and at some point we could be around each other without getting in a fight.
We still hate each other but she lives in another country.
I think having a fights within my own family has shaped my addiction to fighting.
Does anyone else have a similar experience?