I have divined the secret to interacting exclusively with nice people who will never disappoint you.
Pay them.
Karen, the broker who found my new apartment, was a delight. She told anecdotes about working with Jerry Seinfeld and laughed at my jokes. She reassured me that I am a desirable tenant for whom any sane landlord would kill. She negotiated fantastic lease terms. When my check was returned because of a clerical error, she broke the news gently, saying, "I told our accountant that, if it were anyone else, I'd be worried, but since it was you, David, I knew everything would be fine." (And everything was fine.) She asked to come over and meet Goblin. For a while, she telephoned two or three times a day.
All of this cost me only her $2,500 commission, but I am going to see if she would accept $5,000 for a year of friendship.
I love her.