“Consistent, because, let’s face it, if you meet someone tonight and you never see her again or you only meet once more, that’s not friendship. That’s someone you’ve met,” Nelson explains. “Mutual because it has to go both ways. If you are the only one doing the work, it’s not a friendship. Shared because if you are the only one revealing things about yourself, well then this person is a therapist, not a friend. And positive emotion because nobody wants to spend time with Debbie Downer.”