Perfect relationships are rare, if they exist at all. If you are in a perfect relationship, I want to hear from you! There will be parts of a relationship that are testing for both of you. How you handle those potential sources of conflicts, misunderstanding, disagreement or tension has a bearing on the "success" of a relationship.
Those testing aspects are tests of patience and understanding and provides you with an opportunity to come to agreement or find a basis of working together. These aspects of a relationship can be a means of improving and strengthening your character and bringing out the latent capabilities in you.
Long live the imperfect relationship!
NOTE: The above description does not apply to abusive relationships or those that are unhealthy or detrimental to one or both persons.