C.S. Lewis' argues that one of the key ways to work out difficult relationships with others is to recognize that we each have our own fatal flaw.
"You also have a fatal flaw in your character. All the hopes and plans of others have again and again shipwrecked on your character just as your hopes and plans have shipwrecked on theirs. It is no good passing this over with some vague, general admission such as "Of course, I know I have my faults." It is important to realize that there is some really fatal flaw in you: something which gives others the same feeling of despair which their flaws give you. And it is almost certainly something you don't know about--like what the advertisements call "halitosis", which everyone notices except the person who has it..." Read more here.