Pop superstardom, it turns out, did absolutely nothing to improve Sabrina Carpenter's love life. That's the thrust of the singer's shrewd and tangy "Man's Best Friend," which dropped Thursday night, just a year after last summer's chart-topping "Short n' Sweet." The earlier album, which spun off a pair of smash singles in "Espresso" and "Please Please Please," went on to be certified triple platinum and to win two Grammy Awards.