You got the diagnosis. You knew that the other person was "different" or "eccentric" in many ways, but you didn't know why or how. Now you know that you are living with something called obsessive compulsive personality disorder, Asperger syndrome, Asperger's disorder, autism spectrum disorder, schizoid personality disorder, or narcissistic personality disorder.
You might be relieved in many ways. You now can begin to understand why the other person gets frustrated so easily and so quickly. You begin to understand why he or she cannot think in the way that you can think or why he or she seems to be unable to plan out certain things. This person might be hung up on many of the words or sentences that you use. He or she might nitpick the way that you say things. You wonder why this person just can't infer things or read between the lines, like most other people seem to be able to do. You have an explanation for his or her crazy-making and infuriating behaviors.
The person might need an excessive amount of time alone or might prefer to do many activities alone. This person is task oriented and object oriented. He or she rarely listens to your opinion and may ramble on and on about things he or she enjoys. This person never seems to be consistent in thought patterns, moods, morals, and values. He or she is easily defensive and offended. It is difficult to share your own interests in a conversation with people like this, because they are driven to talk only about themselves or things they are interested in. They seem to be in their heads much of the time or might be excessively involved in their hobbies or in their work.