Yeah, drink is often involved but there are also some very angry people around in the world, just waiting like a 'time bomb' for an excuse to 'kick off'
Anger, seems to be the most difficult emotion generally for people to deal with and leads to a lot of displacement.
I think most of us can identify with that feeling of walking around somebody with a 'short fuse' as if the floor were made of 'egg shells' so as not to 'trigger' them off, but it's NO WAY to live a life, especially if that person wasn't prepared to acknowledge they have a problem and seek help.
There are courses and help for people who need 'anger management' help and for some, it may be linked in with a mental illness.

That woman I mentioned was sentenced today.

http://news.bbc.co.uk/1/hi/england/tyne/7974247.stm