Well, alot of it is, my two oldest sons do not get along. Too much brotherly love brings on brotherly blood. I don't know WHY they don't get along, but they don't.
When they were little, they could play together for a bit, but sooner or later, fists were going to fly. I had to play ref when they were little, but in their 20's, I don't.
Middle son is in the Marines and wasn't able to come home for Christmas this year but he is coming home for New Years. I told oldest son and he said he wouldn't be over. That's fine. Each got a day with the family so I don't really mind. At least youngest son can get along with both of them.
Just that tension puts me in a sad mood and I refuse for them to stick me in the middle of their not liking each other. I have better things to do than worry about who's feelings will get hurt and of course if I say anything, I am the bad guy.