[PorkchopDJG]

This is definitely a +EV move.
I like to watch the players when they get dealt their cards and then judge from their action how week or strong they are. Then just before it gets to me I like to look at my hand so the other players aren't staring directly at me when I first see my cards. When the flop comes out I like to watch either a preflop raiser or the better players to see if I can catch anything. I also look to see which other players are looking back at me, other opponents or just the flop.
As others have noted and Caro talks a lot about in his book, a blank stare at the flop usually means the guy missed and if he looks quickly at the flop and then either glances away or at his chips he usually has a good hand or draw.