I read this article a few months back in The Sunday Times ( Times of India ) newspaper under Mind Over Matter section. Brilliant article. Actually awesome. It explains why, at times, people become difficult to handle, and how to handle them.
Give it a try. If you are facing someone who has become difficult lately, then it will definitely help you.
Handling Difficult People
If only everyone could understand this, there won't be any argument at all in this world. More thoughts on this later...