Charlie Puth's show in D.C. was an exercise in the banal and inoffensive

On Friday night, singer-songwriter Charlie Puth opened his set with his debut single, "Marvin Gaye." The doo-wop throwback turns Gaye's name into a clumsy come-on -- "Let's Marvin Gaye and get it on" -- and on the anniversary of his death, one couldn't help but feel that the soul legend was rolling over in his grave.