Subject: Why do Hydrogen bonds give off heat when they form?

I understand that heat is given off when H bonds form, and is taken in 
when H bonds break. Contrary to intuition, which says that it requires 
energy to break a preformed bond, so that heat would be released only when 
the bond is broken, and absorbed by the molecule when the bond is formed. 
Why then does this specific incidence occur with Hydrogen? I don't 
understand the reason behind it. Please make your answer as specific as 
possible... Thanks.

Re: Why do Hydrogen bonds give off heat when they form?