Madi Diaz has this incredible talent: She makes common modern language about romantic relationships sound poetic and emotionally charged. Even therapy-speak that would come off as cringe coming from most people, when harnessed and molded by Diaz, takes on a kind of raw-nerve intimacy that transcends cliché. On “Why’d You Have To Bring Me Flowers,” the final single from this week’s Fatal Optimist, she’s done it again. “My toxic trait is hanging on,” Diaz begins. “Your toxic trait is showing up.”