There are a lot of things to admire about Sia; her powerhouse voice, her artsy music videos, her clever response to the sex- and scandal- hungry celebrity culture that cannibalizes female artists. There are also things about her that may annoy you. For instance her tendency, as a professional songwriter, to engineer every tune for maximum back-row-of-the-stadium bombastic effect. Writing smash hits is her job. The result is that she fills her records with wannabe smashes that never quite get there. Nuance ain’t her bag. Then there’s her relentless positivity. Every song doesn’t have to be the triumphant anthem that scores the sports montage in an underdog movie, Sia. Not that she’s never written about anything dark; Chandelier, her biggest hit, is about her own alcoholism. It’s just that she makes everything sound like, well, the triumphant anthem that scores the sports montage in an underdog movie. This track was originally written for Rihanna, and you can see why she turned it down. Ri-Ri has a healthy sense of nuance, for all of her glamour, and she tends to steer away from the overly uplifting or sentimental. Uplift should be earned, not hammered home. On the other hand, there’s a place in every record library for an album full of nothing but aggressively fist-pumping pop anthems, and it should probably be This Is Acting.