Why people hug: 
Well, the way I see it ... How about an example. You've held a woman close to you right?
You feel good holding her and she feels protected. Protected equals love, love and
security are good. Hugs that are rough (as you said, "squeeze until they burst") is more
of a guy thing. They show how strong they are by squeezing and how tough they are by
holding out and surviving. 

When we are young, we are protect by our parents by being held close. We hear the heart
beat and our minds are taken to the safety of the whom. So a hug combines the best
of protection, love, simplicity of life, caring, security and sometimes passion. 

Hugs, therefore, are the universal median. I feel sorry for those who don't
like hugs and my arms are open to those that do. 
HUGS