"Can We Still Be Friends?"

What is a good friend? I know that a good friend is there for you when you need them.  They are happy no matter where you go or what you do together; you share common interests and values, and are kind and encouraging to each other.  You accept each other for your authentic selves.  You share your lives and make each other laugh. 

How am I doing so far?  Am I hitting most of the "friend" points?  What about sharing thoughts, opinions, feelings and experiences?  So far I'm on board; but is it necessary to continually share all of our complaints, fears, negative experiences and judgments with each other as well?  This is where I begin to back off. 

I guess as long as there is a healthy balance of negative vs positive topics discussed, it could be beneficial and I am certainly willing to lend an ear to a friend that needs to vent or is going through a challenging time.  But what if a friend only tells you the sad stories, the negative parts of their lives, their complaints and judgments of people in their world and the fearful "what ifs" of their nightmares?  What if their lives seem to consist of one unwanted, negative experience after another? 

What about the Law of Attraction?  If we attract what we focus on, do we attract more of the negative events that a pessimistic friend shares?  What about the health problems that are sure to follow someone with this negative mindset?  I know that not everyone is conscious of the importance of being mindful and putting things into perspective but it can be challenging for a mindful friend to keep a positive and grateful vibe around a negative, judgmental friend. 

I guess with effort, one can work on enveloping themselves in a protective shield from unwanted energy.  But once you figure out how to stay in the Vortex as much as possible, you get to really like that feeling of happiness and joy and become protective of it.  You realize who and what detracts from that feeling and tend to slowly but surely avoid them more and more.  Is this selfishness or self care?  Is it considered abandonment or self preservation?

So again, my question remains, "What is a good friend?"