Director Destin Daniel Cretton's first job out of college was working at a halfway home for troubled teens and, rather like author Ken Kesey's stint working at a mental institution, he clearly gained some insight and a fistful of vivid characters from the experience. The resulting film, "Short Term 12," is unlike other "institutionalized" dramas such as "Girl, Interrupted" or "One Flew Over the Cuckoo's Nest" in that it has a lot of sympathy for the young social workers who are doing their best to help the kids in their care — learning to deal with freak-outs, cultivating a sense of humor under fire and finding creative ways to connect with traumatized, defensive kids.