Image While Dirty Grandpa may have found commercial success with its risqué humor, as a connoisseur of quality cinema I found little to appreciate in its crass shock-value approach. Zac Efron's talent is wasted on such an embarrassingly one-dimensional farce. We can chuckle a little at director Dan Mazer's incompetence, but any film that lives or dies on the curses of Disney stars loses the art of true comedy…More