The Celtics are unhappy and frustrated — and they should be

The Celtics are unhappy and frustrated — and they should be  The Boston Globe Marcus Smart was speechless after the Celtics lost yet another game  Boston.com Boston Celtics: With loss to Mavericks, it's officially time to panic  Chowder and Champions Celtics are going from preseason favorites to average disappointments after 20 games  ESPN Full coverage