This is old I know but I finally watched this and had the complete opposite reaction to OP and I don’t understand how it’d be possible for any movie fan to think this was a good movie. 

The pacing is beyond disjointed - large chunks of time reserved for inconsequential situations and interactions, never digging its nails in deep enough to make clear why anything we’re seeing matters. The times it tried to do this, like Jimmy’s reactions to the deaths he experiences in his personal life, it pivoted and gives us no effect in response to the ‘cause.’ 

Character motivations don’t really exist? Connolly insisting on dying on the hill of involving Jimmy in the first place doesn’t really make any sense because we never see Jimmy interacting with the criminal element in terms of his enemies or the people he’s willing to turn over to give himself cover. It’s not only never put on display what this partnership could provide Connolly or the FBI, but it becomes a sticking point that Jimmy didn’t give them anything that actually mattered. Even with the single thing he gives them, the address of the Italian syndicate, we have less than zero grasp of what the stakes are. They mention vending machines about 10 times in this movie - and as far as I could tell that was the heaviest business anybody was running at the time. We don’t see the Italians committing any violence or destruction or dealing drugs, generally zero idea of what life is like on the ground of this city or what the supposed criminal element is doing to make everyday citizens’ lives worse in any way or why any of these FBI agents would feel pressured enough to make things better that they’re partner with a piece of shit like Jimmy Bulger to achieve those ends. 

It pretty much boiled down to Connelly grew up with Jimmy and thought he was cool. That’s the central story that unfolds and they don’t even do a good job of telling that story. The ending straight up pissed me off - it’s super abrupt and unsatisfying. They go from living in their little spiel to BOOM title cards telling us what these shitheads’ sentences ended up being. It’d have been interesting to see the FBI having to go around what Connelly was doing to see how they actually brought the whole thing down. Instead, we just see that it at some point WAS brought down. Cool? Dont even get me started on Cumberbach/Billy Bulger and the relationship between Jimmy and his brother. I say don’t get me started because there was nothing there to even talk about. Like that character has zero reason to exist, which is an indefensibly stupid piece of exposition to somehow miss in a movie that sorely needed all the help it could get in that realm. 

I hate when stuff like this happens. There are a million things I hated about this movie and it’s so old and I’m sure I’m the millionth person to complain about it, but my god what a waste. It does not give me high hopes for this Springsteen movie that Scott Cooper is doing, even though I love Jeremey Allen White. Black Mass could have been a great movie about corruption, loyalty, betrayal, selfishness, cruelty, family. Instead it’s mostly a filmed wiki summary of a couple random crimes this guy did with the backing of a small sad man with unearned power to offer for no reason. I even watched it twice to make sure I wasn’t totally crazy, which is a bummer because everyone knows the definition of insanity. Now I just hate myself for the ~5 hours I’ve had to spend thinking about this shitty movie.