Dustin Hoffman Why the Long Face?

3/15/2012 3:20 PM PDT BY TMZ STAFF
0315_dustin_hoffman_npgNot to beat a dead horse -- but Dustin Hoffman didn't look too happy today in L.A. ... hours after hearing HBO had cancelled his new show "Luck."

As we reported, the network shut down the racetrack-themed series after a 3rd horse died on set.