If you want to have a healthy relationship of any kind whether it be romantic, family, work or otherwise then we all know and understand that good communication is essential to this. What is less known and less practiced is the need for acceptance.
Resistance and conflict come to a relationship primarily through a lack of acceptance of the other person. The more acceptance that you have the more peace and harmony you will have also. Think about this for a second, the reason you would generally get upset with somebody is because they have behaved in a way that did not meet your standard, they have violated one of your rules, or they have behaved in a way you do not approve of, or in other words, you are the one who is actually causing the problems. This is why once a relationship reaches the blame stage it becomes very destructive.
The lesser the need to change somebody and the more accepting of them for who they are, the higher the level of harmony you will have.
The only time you really have any right to become upset at another person's behavior is when a standard has been set, agreed to and then broken, e.g. wedding vows or a contract.
So having said this, the key to a successful relationship then becomes getting to know somebody and accepting them and their standards of behavior before entering into that relationship. If you can’t accept a person for who they are, simply choose not to get involved.
Learn to work on yourself. If you find yourself irritated or angry thank that person for pointing out that is a part of you that still is not at peace and is not accepting. Instead of trying to change the other person, look at how you can change yourself, if you don’t you will continue to experience the same problems over and over.