It’s not easy being an idol. Diana Ross went to the Westside Theater to see her daughter, Tracee Ellis Ross, perform in “Love, Loss, and What I Wore” and almost escaped without incident. But then, an overexcited middle-aged woman started shrieking a shockingly off-key version of “Ain’t No Mountain High Enough” and begged Diana to join in, yelling, “Come on, sing with me. It’s the best song ever!” Without a word, Diana scooted out the door and into her car. Who could blame her for not being in the mood for a duet?