Patriots Day is a surprisingly effective, respectful look at the humans impacted by the 2013 Boston Marathon bombing. Mark Wahlberg plays a composite of every Boston cop, popping up at each crucial moment of the investigation despite being a drunkard on probation, but that’s okay because movies need heroes and this isn’t a documentary. Wahlberg’s fine as the Bostonian Everyman. (Hey, at least it’s not Ben Affleck.) He gives one very effective speech and one very hammy monologue. John Goodman and J.K. Simmons and Michelle Monaghan are all fine playing real people. (Ever since the Commonwealth of Massachusetts started handing out those generous film tax credits, I’ve imagined there’s some guy in Hollywood teaching actors how to do accents by playing them episodes of This Old House.) Unfortunately, the film unravels at the end with a well-intentioned but incredibly overlong U-turn into Dateline-style documentary.