Rubin advises avoiding "happiness leeches" – people who are negative all the time or who act maliciously and can affect your own happiness through their behavior. "I passed on the chance to collaborate with someone on a tempting project, solely because I'd detected strong evidence of happiness leechiness (my diagnosis: grouch with a touch of jerk)," she wrote. "The project would have been fun, short-lived, and not much work, but each short encounter with this person leeched away a small but noticeable measure of my happiness. I followed my resolution, and the minute I hit 'send' on my 'Thanks, but no thanks' email, I felt a big wave of relief."
