Because it's one good performance, everyone else in the movie seems to be just ok or phoning it in or just too big. One good performance makes me separate that one performance because everyone else was just ok. Pacino is the best thing about the movie and I love the music because I love that type of music from that era and I have no problem with the basic plot because it's a simple story but it's just the execution which bugs me. Tonally the movie is all over the place at times, trying to be a serious look at a drug dealer and the situations in our country and cuba at the time that would lead to this, but then at other times it's so over the top it's comical and doesn't really know if it wants to be this serious thing or be this parody of a serious thing which means there are times when everyone feels like they're in different movies doing different things. There are times when Stone seems like he wants to condemn Tony, times where he wants to make him a saint, and other times where he just wants the audience to make their own judgement and you can't have it three ways. Peep Wolf of Wall Street: Scorsese clearly takes a stance on Jordan and the way he does that is by showing how ridiculous and over the top and insane he is and the lengths he was willing to go in order to keep his money and his business. And then in the end, he takes a few jabs at America and the American dream and our justice system etc; he has a point of view and makes sure it's consistent throughout the whole movie. Stone was too coked out to even do that.
And a lot of the dialogue is just too on the nose for me and dialogue is always something that sticks out to me in a movie because that's what I love and I know not everyone feels that way and I'm cool with that, but I just hate on the nose dialogue and like
@kp404 said, the 2nd half of the movie just falls off the rails for me. All the stuff leading up to him becoming the boss is fine but after that it just loses me and bores me after a while.